Electrochemical Fabrication Methods Incorporating Dielectric Materials and/or Using Dielectric Substrates

ABSTRACT

Some embodiments are directed to techniques for building single layer or multi-layer structures on dielectric or partially dielectric substrates. Certain embodiments deposit seed layer material directly onto substrate materials while others use an intervening adhesion layer material. Some embodiments use different seed layer and/or adhesion layer materials for sacrificial and structural conductive building materials. Some embodiments apply seed layer and/or adhesion layer materials in what are effectively selective manners while others apply the materials in blanket fashion. Some embodiments remove extraneous material via planarization operations while other embodiments remove the extraneous material via etching operations. Other embodiments are directed to the electrochemical fabrication of multilayer mesoscale or microscale structures which are formed using at least one conductive structural material, at least one conductive sacrificial material, and at least one dielectric material. In some embodiments the dielectric material is a UV-curable photopolymer.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/185,613 (Microfabrica Docket No. P-US128-I-MF), filed Feb. 20, 2014.The '613 application is a continuation of U.S. patent application Ser.No. 12/770,648 (P-US128-H-MF), filed Apr. 29, 2010, now abandoned. The'648 application is a continuation of U.S. patent application Ser. No.12/015,374 (P-US128-G-MF), filed Jan. 16, 2008, now abandoned. The '374application is a continuation of U.S. patent application Ser. No.11/029,014 (P-US128-E-MF), filed Jan. 3, 2005, now U.S. Pat. No.7,517,462, issued Apr. 14, 2009. The '014 application is a continuationin part of U.S. patent application Ser. No. 10/841,300 (P-US099-A-MF),filed on May 7, 2004, now abandoned; and is a continuation in part ofU.S. patent application Ser. No. 10/607,931 (P-US075-A-MG), filed Jun.27, 2003, now U.S. Pat. No. 7,239,219, issued Jul. 3, 2007. The '014application also claims benefit of U.S. Provisional Patent ApplicationNos. 60/533,932, filed Dec. 31, 2003; 60/534,157, filed Dec. 31, 2003;60/533,891, filed Dec. 31, 2003; and 60/574,733, filed on May 26, 2004.Each of the above noted priority applications are hereby incorporatedherein by reference as if set forth in full.

FIELD OF THE INVENTION

The present invention relates generally to the field of ElectrochemicalFabrication and the associated formation of three-dimensional structures(e.g. microscale or mesoscale structures). More particularly, it relatesto the electrochemical fabrication methods that form structures ondielectric substrates and/or form structures from layers thatincorporate dielectrics.

BACKGROUND OF THE INVENTION

A technique for forming three-dimensional structures (e.g. parts,components, devices, and the like) from a plurality of adhered layerswas invented by Adam L. Cohen and is known as ElectrochemicalFabrication. This technique was described in U.S. Pat. No. 6,027,630,issued on Feb. 22, 2000. This electrochemical deposition techniqueallows the selective deposition of a material using a unique maskingtechnique that involves the use of a mask that includes patternedconformable material on a support structure that is independent of thesubstrate onto which plating will occur. When desiring to perform anelectrodeposition using the mask, the conformable portion of the mask isbrought into contact with a substrate while in the presence of a platingsolution such that the contact of the conformable portion of the mask tothe substrate inhibits deposition at selected locations. Forconvenience, these masks might be generically called conformable contactmasks; and the masking technique may be generically called a conformablecontact mask plating process. More specifically, in the terminology ofMicrofabrica® Inc. of Van Nuys, Calif. such masks have come to be knownas INSTANT MASKS™ and the process known as INSTANT MASKING™ or INSTANTMASK™ plating. Selective depositions using conformable contact maskplating may be used to form single selective deposits of material or maybe used to form multi-layer structures. The teachings of the '630 patentare hereby incorporated herein by reference as if set forth in fullherein. Since the filing of the patent application that led to the abovenoted patent, various papers about conformable contact mask plating(i.e. INSTANT MASKING) and electrochemical fabrication have beenpublished:

-   -   (1) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.        Will, “EFAB: Batch production of functional, fully-dense metal        parts with micro-scale features”, Proc. 9th Solid Freeform        Fabrication, The University of Texas at Austin, p161, Aug. 1998.    -   (2) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.        Will, “EFAB: Rapid, Low-Cost Desktop Micromachining of High        Aspect Ratio True 3-D MEMS”, Proc. 12th IEEE Micro Electro        Mechanical Systems Workshop, IEEE, p244, Jan 1999.    -   (3) A. Cohen, “3-D Micromachining by Electrochemical        Fabrication”, Micromachine Devices, March 1999.    -   (4) G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P.        Will, “EFAB: Rapid Desktop Manufacturing of True 3-D        Microstructures”, Proc. 2nd International Conference on        Integrated MicroNanotechnology for Space Applications, The        Aerospace Co., Apr. 1999.    -   (5) F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P.        Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal        Microstructures using a Low-Cost Automated Batch Process”, 3rd        International Workshop on High Aspect Ratio MicroStructure        Technology (HARMST '99), June 1999.    -   (6) A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P.        Will, “EFAB: Low-Cost, Automated Electrochemical Batch        Fabrication of Arbitrary 3-D Microstructures”, Micromachining        and Microfabrication Process Technology, SPIE 1999 Symposium on        Micromachining and Microfabrication, September 1999.    -   (7) F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P.        Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal        Microstructures using a Low-Cost Automated Batch Process”, MEMS        Symposium, ASME 1999 International Mechanical Engineering        Congress and Exposition, November, 1999.    -   (8) A. Cohen, “Electrochemical Fabrication (EFABTM)”, Chapter 19        of The MEMS Handbook, edited by Mohamed Gad-El-Hak, CRC Press,        2002.    -   (9) Microfabrication—Rapid Prototyping's Killer Application”,        pages 1-5 of the Rapid Prototyping Report, CAD/CAM Publishing,        Inc., June 1999.

The disclosures of these nine publications are hereby incorporatedherein by reference as if set forth in full herein.

An electrochemical deposition process may be carried out in a number ofdifferent ways as set forth in the above patent and publications. In oneform, this process involves the execution of three separate operationsduring the formation of each layer of the structure that is to beformed:

-   -   1. Selectively depositing at least one material by        electrodeposition upon one or more desired regions of a        substrate.    -   2. Then, blanket depositing at least one additional material by        electrodeposition so that the additional deposit covers the one        or more regions that were previously selectively deposited onto,        and the regions of the substrate that did not receive any        previously applied selective depositions.    -   3. Finally, planarizing the materials deposited during the first        and second operations to produce a smoothed surface of a first        layer of desired thickness having at least one region containing        the at least one material and at least one region containing at        least the one additional material.

After formation of the first layer, one or more additional layers may beformed adjacent to the immediately preceding layer and adhered to thesmoothed surface of that preceding layer. These additional layers areformed by repeating the first through third operations one or more timeswherein the formation of each subsequent layer treats the previouslyformed layers and the initial substrate as a new and thickeningsubstrate.

Once the formation of all layers has been completed, at least a portionof at least one of the materials deposited is generally removed by anetching process to expose or release the three-dimensional structurethat was intended to be formed.

One method of performing the selective electrodeposition involved in thefirst operation is by conformable contact mask plating. In this type ofplating, one or more conformable contact (CC) masks are first formed.The CC masks include a support structure onto which a patternedconformable dielectric material is adhered or formed. The conformablematerial for each mask is shaped in accordance with a particularcross-section of material to be plated. In such a process, at least oneCC mask is needed for each unique cross-sectional pattern that is to beplated.

The support for a CC mask is typically a plate-like structure formed ofa metal that is to be selectively electroplated and from which materialto be plated will be dissolved. In this typical approach, the supportwill act as an anode in an electroplating process. In an alternativeapproach, the support may instead be a porous or otherwise perforatedmaterial through which deposition material will pass during anelectroplating operation on its way from a distal anode to a depositionsurface. In either approach, it is possible for CC masks to share acommon support, i.e. the patterns of conformable dielectric material forplating multiple layers of material may be located in different areas ofa single support structure. When a single support structure containsmultiple plating patterns, the entire structure is referred to as the CCmask while the individual plating masks may be referred to as“submasks”. In the present application such a distinction will be madeonly when relevant to a specific point being made.

In preparation for performing the selective deposition of the firstoperation, the conformable portion of the CC mask is placed inregistration with and pressed against a selected portion of (1) thesubstrate, (2) a previously formed layer, or (3) a previously depositedmaterial forming a portion of the given layer that is being created. Thepressing together of the CC mask and substrate, layer, or materialoccurs in such a way that all openings in the conformable portions ofthe CC mask contain plating solution. The conformable material of the CCmask that contacts the substrate, layer, or material acts as a barrierto electrodeposition while the openings in the CC mask that are filledwith electroplating solution act as pathways for transferring materialfrom an anode (e.g. the CC mask support) to the non-contacted portionsof the substrate (which act as a cathode during the plating operation)when an appropriate potential and/or current are supplied.

An example of a CC mask and CC mask plating are shown in FIGS. 1A-10.FIG. 1A shows a side view of a CC mask 8 consisting of a conformable ordeformable (e.g. elastomeric) insulator 10 patterned on an anode 12. Theanode has two functions. FIG. 1A also depicts a substrate 6 separatedfrom mask 8. One is as a supporting material for the patterned insulator10 to maintain its integrity and alignment since the pattern may betopologically complex (e.g., involving isolated “islands” of insulatormaterial). The other function is as an anode for the electroplatingoperation. CC mask plating selectively deposits material 22 onto asubstrate 6 by simply pressing the insulator against the substrate thenelectrodepositing material through apertures 26 a and 26 b in theinsulator as shown in FIG. 1B. After deposition, the CC mask isseparated, preferably non-destructively, from the substrate 6 as shownin FIG. 10.

The CC mask plating process is distinct from a “through-mask” platingprocess in that in a through-mask plating process the separation of themasking material from the substrate would occur destructively. As withthrough-mask plating, CC mask plating deposits material selectively andsimultaneously over the entire layer. The plated region may consist ofone or more isolated plating regions where these isolated platingregions may belong to a single structure that is being formed or maybelong to multiple structures that are being formed simultaneously. InCC mask plating as individual masks are not intentionally destroyed inthe removal process, they may be usable in multiple plating operations.

Another example of a CC mask and CC mask plating is shown in FIGS.1D-1F. FIG. 1D shows an anode 12′ separated from a mask 8′ that includesa patterned conformable material 10′ and a support structure 20. FIG. 1Dalso depicts substrate 6 separated from the mask 8′. FIG. 1E illustratesthe mask 8′ being brought into contact with the substrate 6. FIG. 1Fillustrates the deposit 22′ that results from conducting a current fromthe anode 12′ to the substrate 6. FIG. 1G illustrates the deposit 22′ onsubstrate 6 after separation from mask 8′. In this example, anappropriate electrolyte is located between the substrate 6 and the anode12′, and a current of ions coming from one or both of the solution andthe anode is conducted through the opening in the mask to the substratewhere material is deposited. This type of mask may be referred to as ananodeless INSTANT MASK™ (AIM) or as an anodeless conformable contact(ACC) mask.

Unlike through-mask plating, CC mask plating allows CC masks to beformed completely separate from the substrate on which plating is tooccur (e.g. separate from a three-dimensional (3D) structure that isbeing formed). CC masks may be formed in a variety of ways, e.g. aphotolithographic process may be used. All masks can be generatedsimultaneously, e.g. prior to structure fabrication rather than duringit. This separation makes possible a simple, low-cost, automated,self-contained, and internally-clean “desktop factory” that can beinstalled almost anywhere to fabricate 3D structures, leaving anyrequired clean room processes, such as photolithography to be performedby service bureaus or the like.

An example of the electrochemical fabrication process discussed above isillustrated in FIGS. 2A-2F. These figures show that the process involvesdeposition of a first material 2 which is a sacrificial material and asecond material 4 which is a structural material. The CC mask 8, in thisexample, includes a patterned conformable material (e.g. an elastomericdielectric material) 10 and a support 12 which is made from depositionmaterial 2. The conformal portion of the CC mask is pressed againstsubstrate 6 with a plating solution 14 located within the openings 16 inthe conformable material 10. An electric current, from power supply 18,is then passed through the plating solution 14 via (a) support 12 whichdoubles as an anode and (b) substrate 6 which doubles as a cathode. FIG.2A illustrates that the passing of current causes material 2 within theplating solution and material 2 from the anode 12 to be selectivelytransferred to and plated on the cathode 6. After electroplating thefirst deposition material 2 onto the substrate 6 using CC mask 8, the CCmask 8 is removed as shown in FIG. 2B. FIG. 2C depicts the seconddeposition material 4 as having been blanket-deposited (i.e.non-selectively deposited) over the previously deposited firstdeposition material 2 as well as over the other portions of thesubstrate 6. The blanket deposition occurs by electroplating from ananode (not shown), composed of the second material, through anappropriate plating solution (not shown), and to the cathode/substrate6. The entire two-material layer is then planarized to achieve precisethickness and flatness as shown in FIG. 2D. After repetition of thisprocess for all layers, the multi-layer structure 20 formed of thesecond material 4 (i.e. structural material) is embedded in firstmaterial 2 (i.e. sacrificial material) as shown in FIG. 2E. The embeddedstructure is etched to yield the desired device, i.e. structure 20, asshown in FIG. 2F.

Various components of an exemplary manual electrochemical fabricationsystem 32 are shown in FIGS. 3A-3C. The system 32 consists of severalsubsystems 34, 36, 38, and 40. The substrate holding subsystem 34 isdepicted in the upper portions of each of FIGS. 3A-3C and includesseveral components: (1) a carrier 48, (2) a metal substrate 6 onto whichthe layers are deposited, and (3) a linear slide 42 capable of movingthe substrate 6 up and down relative to the carrier 48 in response todrive force from actuator 44. Subsystem 34 also includes an indicator 46for measuring differences in vertical position of the substrate whichmay be used in setting or determining layer thicknesses and/ordeposition thicknesses. The subsystem 34 further includes feet 68 forcarrier 48 which can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown in the lower portion of FIG. 3A includesseveral components: (1) a CC mask 8 that is actually made up of a numberof CC masks (i.e. submasks) that share a common support/anode 12, (2)precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on whichthe feet 68 of subsystem 34 can mount, and (5) a tank 58 for containingthe electrolyte 16. Subsystems 34 and 36 also include appropriateelectrical connections (not shown) for connecting to an appropriatepower source for driving the CC masking process.

The blanket deposition subsystem 38 is shown in the lower portion ofFIG. 3B and includes several components: (1) an anode 62, (2) anelectrolyte tank 64 for holding plating solution 66, and (3) frame 74 onwhich the feet 68 of subsystem 34 may sit. Subsystem 38 also includesappropriate electrical connections (not shown) for connecting the anodeto an appropriate power supply for driving the blanket depositionprocess.

The planarization subsystem 40 is shown in the lower portion of FIG. 3Cand includes a lapping plate 52 and associated motion and controlsystems (not shown) for planarizing the depositions.

The '630 patent further indicates that the electroplating methods andarticles disclosed therein allow fabrication of devices from thin layersof materials such as, e.g., metals, polymers, ceramics, andsemiconductor materials. It further indicates that although theelectroplating embodiments described therein have been described withrespect to the use of two metals, a variety of materials, e.g.,polymers, ceramics and semiconductor materials, and any number of metalscan be deposited either by the electroplating methods therein, or inseparate processes that occur throughout the electroplating method. Itindicates that a thin plating base can be deposited, e.g., bysputtering, over a deposit that is insufficiently conductive (e.g., aninsulating layer) so as to enable subsequent electroplating. It alsoindicates that multiple support materials (i.e. sacrificial materials)can be included in the electroplated element allowing selective removalof the support materials.

Another method for forming microstructures from electroplated metals(i.e. using electrochemical fabrication techniques) is taught in U.S.Pat. No. 5,190,637 to Henry Guckel, entitled “Formation ofMicrostructures by Multiple Level Deep X-ray Lithography withSacrificial Metal Layers”. This patent teaches the formation of metalstructures utilizing mask exposures. A first layer of a primary metal iselectroplated onto an exposed plating base to fill a void in aphotoresist (the photoresist forming a through-mask having a desiredpattern of openings). The photoresist is then removed and a secondarymetal is electroplated over the first layer and over the plating base.The exposed surface of the secondary metal is then machined down to aheight which exposes the first metal to produce a flat uniform surfaceextending across the both the primary and secondary metals. Formation ofa second layer may then begin by applying a photoresist layer over thefirst layer and then repeating the process used to produce the firstlayer. The process is then repeated until the entire structure is formedand the secondary metal is removed by etching. The photoresist is formedover the plating base or previous layer by casting and the voids in thephotoresist (i.e. voids formed in the photoresist) are formed byexposure of the photoresist through a patterned mask via X-rays or UVradiation and development of the exposed or unexposed areas.

The '637 patent teaches the locating of a plating base onto a substratein preparation for electroplating materials onto the substrate. Theplating base is indicated as typically involving the use of a sputteredfilm of an adhesive metal, such as chromium or titanium, and then asputtered film of the metal that is to be plated. It is also taught thatthe plating base may be applied over an initial sacrificial layer ofmaterial (i.e. a layer or coating of a single material) on the substrateso that the structure and substrate may be detached if desired. In suchcases after formation of the structure the sacrificial material formingpart of each layer of the structure may be patterned and removed fromaround the structure and then the sacrificial layer under the platingbase may be dissolved to free the structure. Substrate materialsmentioned in the '637 patent include silicon, glass, metals, and siliconwith protected processed semiconductor devices. A specific example of aplating base includes about 150 angstroms of titanium and about 300angstroms of nickel, both of which are sputtered at a temperature of160° C. In another example it is indicated that the plating base mayconsist of 150 angstroms of titanium and 150 angstroms of nickel whereboth are applied by sputtering.

Even though electrochemical fabrication as taught and practiced to date,has greatly enhanced the capabilities of microfabrication, and inparticular added greatly to the number of metal layers that can beincorporated into a structure and to the speed and simplicity in whichsuch structures can be made, and even to the incorporation of somedielectric materials, room for enhancing dielectric incorporation and/orbuilding on dielectric substrates exists.

SUMMARY OF THE INVENTION

It is an object of some embodiments of the invention to provide improvedmethods for incorporating dielectrics into a multi-layer electrochemicalfabrication process.

It is an object of some embodiments of the invention to provide improvedmethods for incorporating dielectrics into multi-layer electrochemicallyfabricated structures.

It is an object of some embodiments of the invention to provide improvedmethods for electrochemically fabricating multi-layer structures on adielectric substrate.

Other objects and advantages of various embodiments and aspects of theinvention will be apparent to those of skill in the art upon review ofthe teachings herein. Various embodiments of the invention, set forthexplicitly herein or otherwise ascertained from the teachings herein,may address one or more of the above objects alone or in combination, oralternatively they may address some other object of the inventionascertained from the teachings herein. It is not necessarily intendedthat all objects be addressed by any single aspect of the invention eventhough that may be the case with regard to some aspects.

In a first aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a dielectric substrate or to a substratecontaining at least one region of dielectric material; (b) forming andadhering at least one layer to a previously formed layer to build up athree-dimensional structure from a plurality of adhered layers; whereinthe formation of the first layer of material comprises: (i) depositingan adhesion layer material and/or a seed layer material onto at least aportion of a surface of the substrate; (ii) depositing at least one of astructural material and/or sacrificial material onto at least a portionof an adhesion layer and/or seed layer material; wherein prior tocompletion of formation of a last layer of the structure, removingportions of any adhesion layer material and/or seed layer material fromthe substrate that is not covered by structural material.

In a second aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a substrate; (b) forming an adhering at leastone layer to a previously formed layer to build up a three-dimensionalstructure from a plurality of adhered layers; wherein the formation ofan nth layer comprises: (i) depositing an adhesion layer material and/ora seed layer material onto a surface of the (n−1)th layer; (ii)depositing at least one of a first material and/or a second materialonto at least a portion of the adhesion layer material and/or seed layermaterial; wherein at least one of the first or second materialscomprises a structural material, and wherein prior to completion offormation of a last layer of the structure, removing portions of anyadhesion layer material and/or seed layer material located on thesurface of the (n−1)th layer that is not covered by structural material.

In a third aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a dielectric substrate or to a substratecontaining at least one region of dielectric material; (b) forming anadhering at least one layer to a previously formed layer to build up athree-dimensional structure from a plurality of adhered layers; whereinthe formation of the first layer of material comprises: (i) depositingan adhesion layer material and/or a seed layer material onto at least aportion of a surface of the substrate; (ii) depositing at least one of astructural material and/or sacrificial material onto at least a portionof an adhesion layer and/or seed layer material; (iii) wherein prior tocompletion of formation of the first layer of the structure, removingportions of any adhesion layer material and/or seed layer material fromthe substrate that is not covered by structural material.

In a fourth aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a substrate; (b) forming an adhering at leastone layer to a previously formed layer to build up a three-dimensionalstructure from a plurality of adhered layers; wherein the formation ofan nth layer comprises: (i) depositing an adhesion layer material and/ora seed layer material onto a surface of the (n−1)th layer; (ii)depositing at least one of a first material and/or a second materialonto at least a portion of the adhesion layer material and/or seed layermaterial; wherein at least one of the first or second materialscomprises a structural material, and wherein prior to completion offormation of the nth layer of the structure, removing portions of anyadhesion layer material and/or seed layer material located on thesurface of the (n−1)th layer that is not covered by structural material.

In a fifth aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a dielectric substrate or to a substratecontaining at least one region of dielectric material; (b) forming anadhering at least one layer to a previously formed layer to build up athree-dimensional structure from a plurality of adhered layers; whereinthe formation of the first layer of material comprises: (i) depositingan adhesion layer material and/or a seed layer material to form anon-planar coating of which a portion defines a region of the substratethat is to receive an electrodeposition of a selected one of astructural material or of a sacrificial material.

In a sixth aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a substrate; (b) forming an adhering at leastone layer to a previously formed layer to build up a three-dimensionalstructure from a plurality of adhered layers; wherein the formation ofan nth layer comprises: depositing an adhesion layer material and/or aseed layer material to form a non-planar coating of which a portiondefines a region of an (n−1)th layer that is to receive a deposition ofa selected one of a first or second material.

In a seventh aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a dielectric substrate or to a substratecontaining at least one region of dielectric material; (b) forming anadhering at least one layer to a previously formed layer to build up athree-dimensional structure from a plurality of adhered layers; whereinthe formation of the first layer of material comprises: depositing afirst adhesion layer material and/or a first seed layer material to onlya portion of a surface of the substrate that is to receive eitherstructural material or sacrificial material.

In an eighth aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a substrate; (b) forming an adhering at leastone layer to a previously formed layer to build up a three-dimensionalstructure from a plurality of adhered layers; wherein the formation ofan nth layer comprises: depositing a first adhesion layer materialand/or a first seed layer material to only a portion of a surface of the(n−1)th layer, wherein the portion is that portion which is to receiveeither the first or second material.

In a ninth aspect of the invention a process for forming a multilayerthree-dimensional structure, comprising: (a) forming and adhering afirst layer of material to a substrate; (b) forming an adhering at leastone layer to a previously formed layer to build up a three-dimensionalstructure from a plurality of adhered layers; wherein the formation ofan nth layer comprises: locating a first adhesion layer material and/ora first seed layer material to only a portion of a surface of the(n−1)th layer that is to receive either the first or second material.

In an tenth aspect of the invention a process for forming a multilayerthree-dimensional structure on a dielectric substrate, comprising: (a)forming and adhering a first layer of material to a dielectric substrateor to a substrate containing at least one region of dielectric material;(b) forming and adhering at least one layer to a previously formed layerto build up a three-dimensional structure from a plurality of adheredlayers; wherein the formation of the first layer of material comprises:(i) depositing a first seed layer material onto those portions of asubstrate that are to receive a selected one of structural material or asacrificial material; (ii) depositing the selected one of structuralmaterial or a sacrificial material onto the first seed layer materialover those portions of the substrate that are to receive the selectedone of structural material or a sacrificial material; (iii) removingportions of the first seed layer material that are not located betweenthe selected one and the substrate or located adjacent to the selectedone; (iv) depositing a second seed layer material onto those portions ofthe substrate that are to receive a non-selected one of the structuralmaterial and sacrificial material; (v) depositing a the non-selected oneof structural material or a sacrificial material onto the second seedlayer material over those portions of the substrate that are to receivethe non-selected one of structural material or a sacrificial material;(vi) planarizing the deposited materials to a height corresponding to adesired thickness of the first layer.

In an eleventh aspect of the invention a process for forming andadhering a layer of material to a dielectric substrate or to a substratehaving at least one region of dielectric material, comprising: (a)depositing a first seed layer material onto those portions of asubstrate that are to receive a selected one of structural material or asacrificial material; (b) depositing the selected one of structuralmaterial or a sacrificial material onto the first seed layer materialover those portions of the substrate that are to receive the selectedone of structural material or a sacrificial material; (c) removingportions of the first seed layer material that are not located betweenthe selected one and the substrate or located adjacent to the selectedone; (d) depositing a second seed layer material onto those portions ofthe substrate that are to receive a non-selected one of the structuralmaterial and sacrificial material; (e) depositing a the non-selected oneof structural material or a sacrificial material onto the second seedlayer material over those portions of the substrate that are to receivethe non-selected one of structural material or a sacrificial material;(f) planarizing the deposited materials to a height corresponding to adesired thickness of the layer.

In a twelfth aspect of the invention a fabrication process for forming amulti-layer three-dimensional structure that comprises at least oneconductive structural material and at least one dielectric material,comprising: (a) forming and adhering a layer of material to a previouslyformed layer and/or to a substrate, wherein the layer comprises adesired pattern of at least one material; and (b) repeating the formingand adhering operation of (a) a plurality of times to build up thethree-dimensional structure from a plurality of adhered layers, whereinformation of at least one layer comprises: (i) preparing a surface ofthe substrate or a previously deposited material to for accepting anelectrodeposited conductive material; (ii) depositing a first conductivematerial; (iii) depositing a curable dielectric material on to thesurface of the substrate or previously deposited material; (iv) curingthe dielectric material; and (v) planarizing at least one of thedeposited materials.

In a thirteenth aspect of the invention a fabrication process forforming a multi-layer three-dimensional structure that comprises atleast one conductive structural material and at least one dielectricmaterial, comprising: (a) forming and adhering a layer of material to apreviously formed layer and/or to a substrate, wherein the layercomprises a desired pattern of at least one material; and (b) repeatingthe forming and adhering operation of (a) a plurality of times to buildup the three-dimensional structure from a plurality of adhered layers,wherein formation of at least one layer comprises: (i) preparing asurface of the substrate or a previously deposited material to foraccepting an deposited conductive material; (ii) depositing a firstconductive material; (ii) depositing a dielectric material on to thesurface of the substrate or previously deposited material; and (iv)planarizing at least one of the deposited materials.

In a fourteenth aspect of the invention a process for forming amultilayer three-dimensional structure, comprising: (a) forming andadhering a first layer of material to a substrate; (b) forming anadhering at least one layer to a previously formed layer to build up athree-dimensional structure from a plurality of adhered layers; whereinthe formation of an nth layer comprises the following time orderedoperations: (i) applying a photoresist to a previously depositedmaterial; (ii) exposing the photoresist in a first pattern correspondingto a pattern of a first material to be deposited; (iii) developing thephotoresist to yield opening in the photoresist for receiving the firstmaterial; (iv) exposing the remaining photoresist in a second patterncorresponding to a second material to be deposited; (v) depositing thefirst material; (vi) developing the photoresist to create openingscorresponding to the second pattern; and then (vii) depositing thesecond material.

In a fifteenth aspect of the invention a process for forming amultilayer three-dimensional structure, comprising: (a) supplying asource of a depositable first structural material; (b) supplying asource of a depositable second structural material; (c) supplying asource of a depositable third material that may function as asacrificial material or as a structural material; (d) forming andadhering a plurality of layers to previously formed layers to build up athree-dimensional structure comprising all three materials wherein onany given layer only two of the three materials are deposited; whereinthe structure is formed such that at least a portion of thirddepositable material is encapsulated by one or all of the firstdepositable structural material, the second depositable structuralmaterial and any substrate on which layer formation initiates, andwherein after formation of the layers, a portion of the third materialis removed to at least partially release the structure.

Further aspects of the invention will be understood by those of skill inthe art upon review of the teachings herein. Other aspects of theinvention may involve combinations of the above noted aspects of theinvention. Other aspects of the invention may involve apparatus that canbe used in implementing one or more of the above method aspects of theinvention or may involve structures formed by the method aspects of theinvention. These other aspects of the invention may provide variouscombinations of the aspects presented above as well as provide otherconfigurations, structures, functional relationships, and processes thathave not been specifically set forth above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CCmask plating process, while FIGS. 1D-1G schematically depict a sideviews of various stages of a CC mask plating process using a differenttype of CC mask.

FIGS. 2A-2F schematically depict side views of various stages of anelectrochemical fabrication process as applied to the formation of aparticular structure where a sacrificial material is selectivelydeposited while a structural material is blanket deposited.

FIGS. 3A-3C schematically depict side views of various examplesubassemblies that may be used in manually implementing theelectrochemical fabrication method depicted in FIGS. 2A-2F.

FIGS. 4A-4G schematically depict the formation of a first layer of astructure using adhered mask plating where the blanket deposition of asecond material overlays both the openings between deposition locationsof a first material and the first material itself while FIG. 4H depictsthe state of the process after formation of a plurality of additionallayers and FIG. 41 depicts the state of the process after removal of thesecond material.

FIG. 5A provides a block diagram indicating the two main approaches forbuilding on a dielectric or partially dielectric substrate according tovarious embodiments of the invention.

FIG. 5B provides a block diagram indicating three exampleimplementations associated with the first of the main approaches setforth in FIG. 5A.

FIG. 5C provides a block diagram indicating four example implementationsassociated with the second of the main approaches set forth in FIG. 5A.

FIG. 5D provides a block diagram indicating four more detailedimplementation examples associated with the first example implementationof FIG. 5C.

FIG. 5E provides a block diagram indicating three more detailedimplementation examples (one of which is indicated as having twoalternatives) associated with the second example implementation of FIG.5C.

FIG. 5F provides a block diagram indicating a more detailedimplementation example (along with two alternatives therefore)associated with the third example implementation of FIG. 5C.

FIG. 5G provides a block diagram indicating a more detailedimplementation example (along with two alternatives therefore)associated with the fourth example implementation of FIG. 5C.

FIGS. 6A-6J provide schematic illustrations of side views at variousstages of the process of a first embodiment of the invention whichprovides a first implementation of the example of block 122 of FIG. 5B.

FIGS. 7A-7J provide schematic illustrations of side views at variousstages of the process of a second embodiment of the invention whichprovides a first implementation of the example of block 124 of FIG. 5B.

FIGS. 8A-8J provide schematic illustrations of side views at variousstages of the process of a third embodiment of the invention whichprovides a first implementation of the example of block 126 of FIG. 5B.

FIGS. 9A-9D provide schematic illustrations of side views at variousstages of the process of a fourth embodiment of the invention whichprovides a first implementation of the example of block 144 of FIG. 5D.

FIGS. 10A-10L provide schematic illustrations of side views at variousstages of the process of a fifth embodiment of the invention whichprovides a first implementation of the example of block 146 of FIG. 5D.

FIGS. 11A-11K provide schematic illustrations of side views at variousstages of the process of a sixth embodiment of the invention whichprovides a first implementation of the example of block 148 of FIG. 5D.

FIGS. 12A-12I provide schematic illustrations of side views at variousstages of the process of a seventh embodiment of the invention whichprovides a second implementation of the example of block 148 of FIG. 5D.

FIGS. 13A-13M provide schematic illustrations of side views at variousstages of the process of an eighth embodiment of the invention whichprovides a first implementation of the example of block 150 of FIG. 5D.

FIGS. 14A-14N provide schematic illustrations of side views at variousstages of the process of a ninth embodiment of the invention whichprovides a first implementation of the example of block 154 of FIG. 5E.

FIGS. 15A-15N provide schematic illustrations of side views at variousstages of the process of a tenth embodiment of the invention whichprovides a first implementation of the example of block 156 of FIG. 5E.

FIGS. 16A-16M provide schematic illustrations of side views at variousstages of the process of an eleventh embodiment of the invention whichprovides a first implementation of the example of block 164 of FIG. 5F.

FIGS. 17A-17N provide schematic illustrations of side views at variousstages of the process of a twelfth embodiment of the invention whichprovides a first implementation of the example of block 166 of FIG. 5F.

FIGS. 18A-18L provide schematic illustrations of side views at variousstages of the process of a thirteenth embodiment of the invention whichprovides a first implementation of the example of block 176 of FIG. 5F.

FIGS. 19A-19D provide schematic illustrations of side views at variousstages of the process of a fourteenth embodiment of the invention whichprovides a first implementation of the example of block 178 of FIG. 5F.

FIGS. 20A-20L provide schematic illustrations of side views at variousstages of the process of a fifteenth embodiment of the invention whichprovides a first implementation of the example of block 184 of FIG. 5G.

FIG. 21 provides a block diagram that sets forth primary operationsassociated with a process for forming a multi-layer structure accordingto another embodiment of the invention.

FIGS. 22A-22H provide schematic illustrations of side views at variousstages of the process of an implementation of an embodiment of theinvention which provides for incorporating a dielectric material alongwith conductive materials on arbitrary layers of a structure beingformed.

FIG. 23 provides a block diagram that sets forth primary operationsassociated with a process for forming a multi-layer structure accordingto an embodiment of the invention where seed layer materials aretailored for receiving specific building materials and where afterdeposition of the associated building material, exposed portions of thecorresponding seed layer material is removed.

FIGS. 24A-24J illustrate an embodiment of the invention where the lowerlayers of a structure are formed with a 1^(st) conductive material and adielectric material while the upper layers of a structure are formedfrom 1^(st) and 2^(nd) conductive materials where the 1^(st) conductivematerial in the lower portion of the structure will be a structuralmaterial and the 1^(st) conductive material in the upper portions willbe removed as a sacrificial material.

FIGS. 25A-25H and FIGS. 26A-26J depict process flows associated with twoalternative embodiments of the invention for working with threematerials on a single layer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form ofelectrochemical fabrication that are known. Other electrochemicalfabrication techniques are set forth in the '630 patent referencedabove, in the various previously incorporated publications, in variousother patents and patent applications incorporated herein by reference,still others may be derived from combinations of various approachesdescribed in these publications, patents, and applications, or mayotherwise be known or otherwise be ascertainable by those of skill inthe art from the teachings set forth herein. All of these techniques maybe combined with those of the various embodiments of various aspects ofthe invention to yield enhanced embodiments. Still other embodiments maybe derived from combinations of the various embodiments explicitly setforth herein.

FIGS. 4A-4G illustrate various stages in the formation of a single layerof a multi-layer fabrication process where a second metal is depositedon a first metal as well as in openings in the first metal where itsdeposition forms part of the layer. In FIG. 4A, a side view of asubstrate 82 is shown, onto which patternable photoresist 84 is cast asshown in FIG. 4B. In FIG. 4C, a pattern of resist is shown that resultsfrom the curing, exposing, and developing of the resist. The patterningof the photoresist 84 results in openings or apertures 92(a)-92(c)extending from a surface 86 of the photoresist through the thickness ofthe photoresist to surface 88 of the substrate 82. In FIG. 4D, a metal94 (e.g. nickel) is shown as having been electroplated into the openings92(a)-92(c). In FIG. 4E, the photoresist has been removed (i.e.chemically stripped) from the substrate to expose regions of thesubstrate 82 which are not covered with the first metal 94. In FIG. 4F,a second metal 96 (e.g., silver) is shown as having been blanketelectroplated over the entire exposed portions of the substrate 82(which is conductive) and over the first metal 94 (which is alsoconductive). FIG. 4G depicts the completed first layer of the structurewhich has resulted from the planarization of the first and second metalsdown to a height that exposes the first metal and sets a thickness forthe first layer. In FIG. 4H the result of repeating the process stepsshown in FIGS. 4B-4G several times to form a multi-layer structure areshown where each layer consists of two materials. For most applications,one of these materials is removed as shown in FIG. 41 to yield a desired3-D structure 98 (e.g. a component or a device).

The various embodiments, alternatives, and techniques disclosed hereinmay form multi-layer structures using a single patterning technique onall layers or using different patterning techniques on different layers.For example, different types of patterning masks and masking techniquesmay be used or even techniques that perform direct selective depositionswithout the need for masking may be used. For example, the methodsdisclosed herein for incorporating dielectrics may be used incombination with conformable contact masks and/or non-conformablecontact masks and masking operations on all, some, or even no layers.Proximity masks and masking operations (i.e. operations that use masksthat at least partially selectively shield a substrate by theirproximity to the substrate even if contact is not made) may be used,and/or adhered masks and masking operations (masks and operations thatuse masks that are adhered to a substrate onto which selectivedeposition or etching is to occur as opposed to only being contacted toit) may be used.

FIG. 5A provides a block diagram indicating the two main approaches forbuilding on a dielectric or partially dielectric substrate according tovarious embodiments of the invention. FIG. 5A provides a first block 100that sets forth the goal of various embodiments of the present inventionwhich is to form a multi-layer structure on a dielectric substrate orsubstrate where at least part of the surface is dielectric.

From block 100 two alternative processes 120 and 140 exist. A first suchprocess uses a seed layer (SL) that is made up of a single material orsingle seed layer material (SLM). In such embodiments a relationshipbetween the material to be deposited and the substrate exists such thata single seed layer material may function as a surface onto whichelectrochemical operations may be performed (e.g. electroplating) aswell as providing adequate adhesion to the substrate material.

The second major alternative represented by block 140 calls for the useof a seed layer stack (SLS) which includes at least two materials. Oneof the materials is a seed layer material itself (i.e. a layer, acoating, or a deposit upon which electrochemical operations may beperformed, e.g. upon which electroplating operations may be performed).The other material is an adhesion layer material which is to be locatedbetween the substrate and the seed layer material. The adhesion layermaterial is typically very thin (e.g. between about 100-1,000 angstromsin thickness) but in some cases thinner or thicker adhesion layers maybe used. Adhesion layer materials may consist of a variety of pure ormixed metals such as, for example, titanium, chromium, ortitanium-tungsten (Ti—W).

In these alternatives seed layer thicknesses typically range from about0.1 microns to 1 micron but in certain cases thinner or thicker seedlayers may be useable and appropriate. In various embodiments to bediscussed hereafter seed layer material may take on many different formsand may actually be different in different portions of a layer andparticularly depending on what materials the seed layers are intended tobound. For example, in some embodiments seed layers may consist ofmaterial that is supplied, for example, by sputtering, electrolessdeposition, or direct metallization. In other embodiments the seed layermaterial may be applied by use of an electroplating strike (e.g. anickel strike such as a Woods strike). The seed layer material may, forexample, include one of the metals that will eventually beelectrodeposited such as the conductive structural material or theconductive sacrificial material. In other embodiments the seed layermaterial may be different from the metals that will form the bulk of thestructural material or the bulk of the sacrificial material. Forexample, in some embodiments the structural material may be nickel whilethe sacrificial material is copper and the seed layer material is gold.

In still other embodiments the seed layer material may be a mixture ofboth the conductive structural and conductive sacrificial materials suchas, for example, a copper nickel alloy.

FIG. 5B provides a block diagram indicating three exampleimplementations associated with the first of the main approaches setforth in FIG. 5A.

Blocks 122, 124, and 126 of FIG. 5B provide example implementations thatfall within the scope of the first main approach of block 120 of FIG.5A. Each of the example implementations 122-126 call for the use of anetch stop or sacrificial material etching barrier layer in addition tothe use of a seed layer material. The seed layer in these exampleimplementations is a copper nickel alloy, the sacrificial material iscopper and the structural material is nickel. In these embodiments theseed layer material exists between the substrate and the structuralmaterial and as the seed layer is relatively thick and is attackable bythe etchant used to remove the sacrificial material, a barrier layerwill be made to exist between the sacrificial material and the seedlayer material in those regions of the layer not occupied by structuralmaterial such that the bulk of the sacrificial material can be removedprior to removal of the etch stop and thereafter the seed layer can beremoved from the sacrificial material regions.

The alternative of block 122 is based on the blanket deposition of asacrificial material etching barrier followed by selective etching ofthe etching barrier in those portions of the layer to be occupied bystructural material. The alternative of block 124 achieves the sameresult of that of block 122 but is based on the pattern deposition ofthe etching barrier material. The alternative of block 126 also achievesthe same result but is based on the patterned deposition of a structuralmaterial followed by the deposition of the etching barrier material intothe voids of the sacrificial material. More specifically the process ofblock 122 includes:

-   -   (1) Supply a dielectric substrate on which a multi-layer        structure is to be formed.    -   (2) Apply a seed layer of a thin film of a copper alloy such as        a copper nickel alloy. The thin film may be deposited by        sputtering or by some other appropriate means. The film        thickness is preferably less then about 1,000 angstroms and more        preferably between about 300-500 angstroms. In some embodiments        the thickness may be as low as 100 angstroms or potentially even        lower while in other embodiments the thickness may exceed 1,000        angstroms. It is preferred that the seed layer be thin enough so        as to affectively limit its etching in areas where it is        sandwiched between structural material and the substrate. The        seed layer material is also thin enough such that excessive        stress in the deposit is not allowed to build up.    -   (3) Next an etch stop material is plated over the seed layer        material. The etch stop material may have a thickness in the        range of 3 to 5 microns in some embodiments and less in other        embodiments or even greater in still other embodiments. For a        nickel structural material and a copper sacrificial material a        potential etching barrier material is tin—as copper may be        etched from tin without damaging it.    -   (4) After deposition of the barrier layer a sacrificial material        (SacMat) is selectively plated onto a portion of the etch stop        material. The selective plating of the sacrificial material may        occur via an adhered mask or a contact mask or in some other        manner.    -   (5) Next, before or after removing any mask, regions of the etch        stop material (ESM) that are not covered by deposited        sacrificial material (i.e. the exposed regions of the ESM) are        removed to expose the seed layer material in those regions. The        removal of the ESM may occur, for example, by chemical etching        or by electrochemical etching. The etching must be performed in        a controlled manner so that excessive undercutting of the        sacrificial material is avoided.    -   (6) Next structural material is plated onto the seed layer        material in the void regions of the sacrificial and barrier        materials.    -   (7) The formation of the first layer over the substrate is        completed by planarizing the deposited materials to a height        corresponding to the layer thickness (LT) of the structure.        Planarization may occur in a variety of ways, for example, by        lapping, by chemical mechanical polishing, grinding, other        machining operations and the like.    -   (8) After completion of the first layer additional layers are        added as appropriate. In the present embodiment those additional        layers are considered to consist of a conductive structural        material and a conductive sacrificial material. In other        embodiments the added layers may consist of multiple conductive        structural materials, multiple conductive sacrificial materials,        and/or one or more dielectric structural or sacrificial        materials.    -   (9) After formation of a desired number of layers, sacrificial        material is removed, for example, by chemical or electrochemical        etching such that the etch stop material is exposed.    -   (10) Next the etch stop material is removed, for example, by        chemical or electrochemical etching so as to expose portions of        the seed layer material located between regions where structural        material overlays the seed layer material.    -   (11) Finally, the exposed portions of the seed layer material        are removed, for example, via chemical or electrochemical        etching. Once this seed layer is removed, separate regions of        conductive structural material become electrically isolated from        one another. With a copper nickel alloy seed layer material the        etching may occur via the same chemical etchant that may be used        to remove the copper sacrificial material. For example, copper        etchant C-38, from Enthone of West Haven, Connecticut with or        without an added corrosion inhibitor that minimizes damage to        the nickel structural material.    -   (12) Various alternatives of this process are possible. For        example, instead of using a single seed layer material, a seed        layer stack may be used such as a titanium or chromium adhesion        layer and a gold seed layer.

FIGS. 6A-6J provide schematic illustrations of side views of a samplestructure at various stages of fabrication according to the process ofthe first embodiment of the invention.

FIG. 6A shows the state of the process after a dielectric substrate 202has been supplied. For illustrative purposes the dielectric substrate202 is shown as resting upon and being surrounded by a conductivematerial 204 to which electrical contact may be made for the purposes ofperforming plating operations and the like.

FIG. 6B shows the state of the process after a seed layer material 206has been blanket deposited over the surface of the dielectric substrate202.

FIG. 6C shows the state of the process after a barrier layer or etchstop layer 208 has been blanket deposited over seed layer material 206.

FIG. 6D shows the state of the process after a sacrificial material 212has been selectively deposited onto the barrier layer and after any maskused during the selective deposition process has been removed.

FIG. 6E shows the state of the process after exposed portions of theetch stop material 208 have been removed from voids 214.

FIG. 6F shows the state of the process after a conductive material 216has been deposited onto exposed regions of seed layer material thatexisted within voids 214.

FIG. 6G shows the state of the process after at least one additionallayer of structural and sacrificial conductive materials have beendeposited (this addition could be formed from one layer or multiplelayers with each having the same cross-sectional configuration).

FIG. 6H shows the state of the process after sacrificial material 212has been removed leaving behind a substantially released structureconsisting of structural material 208 which has isolated regions stillin conductive contact with one another via seed layer 206 and etch stopmaterial 208.

FIG. 6I shows the state of the process after the etch stop material 208has been removed, for example, via chemical etching.

FIG. 6J shows the state of the process after the structure 222 has beenfully released from the sacrificial material and from the interveningareas of the etch stop material and the seed layer material.

Turning back to FIG. 5B block 124 indicates that a second approach tothe process of block 120 involves the patterned deposition of theetching barrier material to regions that will be overlaid by sacrificialmaterial. A process for implementing this approach may include thefollowing operations:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply a seed layer of a copper nickel alloy.    -   (3) Locate a patterned mask on the surface of the substrate such        that openings in the mask material exist over regions to be        occupied by sacrificial material.    -   (4) Plate an etch stop material onto the seed layer material in        the regions of the voids in the masking material.    -   (5) Plate sacrificial material into the regions of the voids in        the mask. The depth of deposition is preferably somewhat greater        then one layer thickness (LT).    -   (6) Next remove the mask material used in the selective        depositions of operations 4 and 5.    -   (7) Deposit a structural material into the voids in the        sacrificial and barrier materials.    -   (8) Planarize the deposits of material to a level corresponding        to LT.    -   (9) Add additional layers onto the first layer that was        completed by the planarization of operation 8.    -   (10) After formation of a desired number of layers (e.g. those        necessary to form the complete structure), remove the        sacrificial material by, for example, chemical etching so as to        expose the etch stop material.    -   (11) Remove the etch stop material, for example, by chemical        etching to expose portions of the seed layer material.    -   (12) Remove the exposed portions of the seed layer material, for        example, by chemical etching so as to complete the release and        electrical isolation of separate portions of the structure.

FIGS. 7A-7J provide schematic illustrations of side views of a samplestructure at various stages of fabrication according to the process ofthe second embodiment of the invention.

FIG. 7A depicts the state of the process after a substrate 232 supportedby conductive carrier 234 is supplied.

FIG. 7B shows the state of the process after a seed layer 236 is blanketdeposited onto the surface of substrate 232.

FIG. 7C shows the state of the process after a patterned mask 240 isapplied to the surface of the seed layer material located on substrate232 and after a barrier layer material 238 has been deposited to theseed layer material in the regions of voids 244.

FIG. 7D depicts the state of the process after a sacrificial material242 has been deposited over etch stop material 238.

FIG. 7E shows the state of the process after the masking material 240has been removed resulting in formation of voids 250 over portions ofthe seed layer material where structural material is to be plated.

FIG. 7F depicts the state of the process after a structural material 246has been deposited onto seed layer 236 and the deposits have beenplanarized to a level corresponding to the layer thickness.

FIG. 7G-7J are analogous to FIG. 6G-6J and show the fully releasedstructure 252 and as such no further description of these figures willbe provided at this time.

Turning back to FIG. 5B, block 126 indicates that the third approach tothe process of block 120 involves the patterned deposition of astructural material followed by the deposition of an etching barrier oretch stop material into the voids located adjacent to the selectivelydeposited structural material. A process implementing the approach ofblock 126 may include the following operations:

-   -   (1) Supply a dielectric substrate.    -   (2) Blanket deposit a seed layer of a copper nickel alloy.    -   (3) Apply and pattern a mask on the copper nickel alloy seed        layer so regions to be occupied by structural material are        exposed via openings or voids in the mask material.    -   (4) Plate the structural material onto the seed layer material        via the voids in the mask. The plating depth is preferably equal        to, or greater than, the layer thickness plus an incremental        amount δ.    -   (5) Remove the mask from the partially formed structure to        reveal exposed regions of the seed layer material via voids in        the structural material.    -   (6) Plate an etch stop material onto the seed layer via the        voids in the structural material. This plating operation may be        of a selective type or may be a blanket deposition operation        that results in the plating of the etch stop material over the        structural material as well as into the void regions. The height        of deposition of the etch stop material is preferably as thin as        possible but sufficient to yield the desired property that its        presence can act as a barrier to an etchant used to remove the        sacrificial material from reaching the seed layer material. The        thickness of the etch stop material, for example, may be on the        order of a tenth of a micron to about a micron and a half but is        more preferably in the range of about 0.3 microns to 0.5        microns.    -   (7) After the plating of the etch stop material the sacrificial        conductive material is plated above the etch stop material and        potentially over the structural material. The height of        deposition in the void regions of the structural material        results in the depositions reaching a height of preferably at        least one layer thickness plus an incremental amount δ.    -   (8) After deposition of the sacrificial material the formation        of the first layer over the substrate is completed by        planarizing the deposits to a height equal to that of the layer        thickness.    -   (9)-(12) After formation of the first layer the process        continues in a similar manner to that described above with        regard to the first and second embodiments. In other words the        process continues with the addition of one or more layers of        material, the etching of the sacrificial material to expose the        etch stop material, the etching through the etch stop material        to expose the seed layer material and finally the etching of the        exposed portions of the seed layer material to produce a        released structure with separate regions of structural material        being conductively uncoupled from one another.

FIGS. 8A-8J provide schematic illustrations of side views of a samplestructure at various stages of fabrication according to the process ofthe third embodiment of the invention.

FIG. 8A depicts the state of the process after a dielectric substrate262 and a conductive carrier 264 is supplied.

FIG. 8B depicts the state of the process after a seed layer material 266(e.g. a copper nickel alloy) is supplied to the surface of substrate262.

FIG. 8C shows the state of the process after a masking material 270 isapplied and patterned on the surface of seed layer material 266 andstructural material 276 is deposited onto the seed layer via theopenings in mask material 270.

FIG. 8D depicts the state of the process after the masking material hasbeen removed and an etch stop material 268 has been plated over exposedregions of the seed layer as well as over the deposited structuralmaterial.

FIG. 8E shows the state of the process after a sacrificial material 272has been blanket deposited over the etch stop material.

FIG. 8F depicts the state of the process after a planarization operationtrims the height of the deposits to that corresponding to a layerthickness LT.

FIGS. 8G-8J are analogous to FIGS. 7G-7J and 6G-6J. These figures depictthe states of the process after formation of an additional layer (FIG.8G), after etching of the sacrificial material (FIG. 8H), after etchingof the etch stop material (FIG. 8I), and finally after removal ofexposed portions of the seed layer material to yield a released object282 with separated portions of the structure being conductively isolatedfrom one another.

FIG. 5C provides a block diagram indicating four example implementationsassociated with the second of the main approach (block 140) set forth inFIG. 5A.

Block 142 represents a first implementation example associated with theuse of a seed layer stack of materials as opposed to a single seed layermaterial. Block 142 calls for the use of a seed layer material (SLM) andadhesion layer material (ALM) which are blanket deposited across theentire substrate. In other words, in this implementation (i.e. group ofembodiments) both the adhesion layer and seed layer materials areinitially located under both sacrificial material regions and structuralmaterial regions of the first layer.

A second implementation example is set forth in block 152 which callsfor an adhesion layer material to cover the entire substrate while afirst seed layer material only covers regions to be occupied by one ofthe structural material or the sacrificial material and where aseparately applied second seed layer material will cover the other ofthe regions.

A third implementation example is called for by block 172. In this thirdexample a first seed layer stack of materials is applied to a firstportion of the substrate to allow deposition of a first selectedmaterial to that portion of the substrate after which a second seedlayer stack of materials is applied to a second portion of the substrateto allow deposition of a second selected material to regions of thesecond portion.

A fourth implementation example is called for by block 182. In thisfourth example a seed layer material and an adhesion layer material areused in association with one of the structural material or sacrificialmaterial while only a seed layer material is used in association withthe other of the structural material or sacrificial material.

FIG. 5D provides a block diagram indicating four more detailedimplementation examples associated with the first example implementation(block 142) of FIG. 5B.

The first more detailed implementation is set forth in block 144. Thisfirst detailed implementation represents the fourth embodiment of theinvention. In this embodiment exposed portions of the seed layermaterial and then the adhesion layer material are removed afterformation of the last layer of the structure and after removal of thesacrificial material.

FIGS. 9A-9D provide schematic illustrations of side views at variousstages of the process of an example of this fourth embodiment of theinvention.

FIG. 9A depicts the state of the process after substrate 302 is providedand a seed layer stack 304 is located thereon.

FIG. 9B depicts the state of the process after the layer build up of astructure 306 is completed where the layers include structural material308 and sacrificial material 310.

FIG. 9C depicts the state of the process after the sacrificial materialhas been separated from the structural material 308 leaving behind thestructure 306 sitting on seed layer stack 304 and on substrate 302.

FIG. 9D shows the final state of the process after exposed regions ofseed layer stack materials have been removed to leave behind adiscontinuous seed layer 304′ which is sandwiched between structuralmaterial 308 and substrate 302.

Block 146 of FIG. 5D sets forth a second more detailed implementationapproach to that set forth in block 142. For the purposes of thisapplication block 146 may be considered to set forth a fifth embodimentof the invention which calls for the removal of those portions of theseed layer material not overlaid by structural material where theremoval is to occur prior to formation of the last layer of thestructure. After removal of the exposed seed layer material, a differentseed layer material is applied over at least the exposed portions of theadhesion layer material.

In some embodiments the removal of the seed layer material may occurafter deposition of a structural material on the first layer and priorto beginning formation of a second layer of the structure. Moreparticularly in some variations of this embodiment the structuralmaterial of the first layer may be deposited prior to the deposition ofsacrificial material on the first layer and thus the seed layer materialmay be removed prior to deposition of the sacrificial material.

In other variations of this embodiment the structural material on thefirst layer may be deposited after an initial deposition of sacrificialmaterial on the first layer after which the initial deposition ofsacrificial material may be removed along with the underlying seed layermaterial which may then be followed by deposition of the second seedlayer material and re-deposition of sacrificial material. Animplementation of embodiment 5 may include the following operation:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply an adhesion layer to the surface of the substrate and        then apply a seed layer to the adhesion layer. In some        variations of this implementation the adhesion layer material        may be titanium or chromium while the seed layer material may,        for example, be gold.    -   (3) Apply a pattern of masking material to the surface of the        substrate (i.e. the surface of the seed layer material). The        pattern of the masking material leaves the seed layer material        exposed in those regions where structural material is to be        deposited.    -   (4) Plate the structural material onto the exposed portions of        the seed layer via the voids or openings in the masking        material.    -   (5) Remove the masking material to expose portions of the seed        layer where a sacrificial material is to be located.    -   (6) Remove exposed regions of the seed layer material, for        example, via a controlled etching operation that limits damage        to boundary regions of the seed layer material that underlie the        structural material.    -   (7) Deposit a different seed layer material onto the exposed        surfaces of the adhesion layer material and possibly onto the        side walls and outward facing surface of the structural        material.    -   (8) Deposit a sacrificial material, for example, by        electroplating in a selective or blanket manner such that the        depth of deposition in the regions where the second seed layer        material overlays the adhesion layer material is greater than or        equal to the layer thickness LT and more preferably greater than        or equal to LT plus an incremental amount δ.    -   (9) Planarize the deposited materials to a height equal to that        of the layer thickness LT, to complete formation of the first        layer.    -   (10) Form any additional layer or layers required to complete        build up of the structure.    -   (11) Remove the sacrificial material, for example, by etching.    -   (12) Remove the second seed layer material for example by        etching.    -   (13) Remove the exposed portions of the adhesion layer material        to complete formation and release of the structure such that        separate portions of the structure are conductively isolated        from other portions of the structure.

FIGS. 10A-10L provide schematic illustrations of side views at variousstages of the process of an example of this fifth embodiment of theinvention which provides a first implementation of the example of block146 of FIG. 5D.

FIG. 10A shows the state of the process after the supplying of asubstrate 322.

FIG. 10B shows the state of the process after an adhesion layer 324 isformed above substrate 322 and a seed layer 326 is formed above adhesionlayer 324.

FIG. 10C shows the state of the process after a patterned mask 328 isapplied to the surface of seed layer 326 wherein openings 330 exist inthe mask which leave the portions of seed layer 326 exposed where astructural material is to be deposited.

FIG. 10D shows the state of the process after a structural material 332is deposited to a depth at least as great as a layer thickness and morepreferably at least as great as a layer thickness plus an incrementalamount O.

FIG. 10E shows the state of the process after mask 328 is removed whichexposes those portions of seed layer 326 where a sacrificial material isto exist on layer 1.

FIG. 10F depicts the state of the process after exposed portions of seedlayer material 326 are removed. As indicated in FIG. 10F slightundercutting 334 may exist in a seed layer material located between thestructural material and substrate as a result of the removal operationbut using controlled etching operations it is believed that thisundercutting can be held to a minimum and will not have a significantlynegative impact on the formation of most structures.

FIG. 10G depicts the state of the process after a second seed layer 338is deposited over adhesion layer 334 as well as over the side walls andoutward facing surface of structural material 332.

FIG. 10H depicts the state of the process after a sacrificial material342 is blanket deposited over the second seed layer material such thatvoids in the structural material 332 are filled to a height equal to orgreater than the layer thickness and more preferably equal to or greaterthan layer thickness plus an incremental amount.

FIG. 10I shows the state of the process after a planarization operationtrims the deposit heights to match the level associated with a layerthickness LT.

FIG. 10J depicts the state of the process after an additional layer isadded to the structure.

FIG. 10K depicts the state of the process after sacrificial material hasbeen removed and FIG. 10L depicts a state of the process after thesecond seed layer material 338 has been removed.

Turning back to FIG. 5D, block 148 sets forth attributes associated witha third group of implementations of approach 142. The attributes includethe removal of a first seed layer material and an associated adhesionlayer material prior to the formation of the last layer of the structureand then the re-application of the adhesion layer material or theapplication of a different adhesion layer material in a blanket mannerfollowed by the re-application of the seed layer material or theapplication of a different seed layer material either of which may occurin a blanket or selective manner. The regions from which the first seedlayer and adhesion layer materials are to be removed may be thoseregions to be overlaid by the conductive sacrificial material or theconductive structural material. The process of block 148 gives rise tomultiple embodiments of the present invention. The two embodiments to bediscussed herein next (embodiment 6 and embodiment 7) are based on theapproach of block 148.

A sixth embodiment of the invention involves the deposition of asacrificial material onto a first layer prior to the deposition of astructural material. Operations associated with the sixth embodimentinclude the following:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply a desired seed layer stack to the substrate. For        example, the seed layer stack may include a titanium adhesion        layer material and a gold seed layer material.    -   (3) Locate and pattern a masking material on the surface of the        seed layer. The patterning of the mask material leaves portions        of the seed layer material exposed and particularly leaves those        portions of the seed layer exposed where a sacrificial material        is to be deposited.    -   (4) Plate sacrificial material onto the seed layer material via        the openings in the mask.    -   (5) Remove the masking material from the seed layer material.    -   (6) Blanket deposit or selectively deposit structural material        such that exposed regions of the seed layer material are coated        with structural material such that a net height of deposition in        those regions equals or exceeds that of a layer thickness LT and        more preferably LT+δ.    -   (7) Planarize the deposited materials to a height of LT+δ.    -   (8) Remove the deposited sacrificial material for example by        etching so as to expose the underlying portions of the seed        layer material.    -   (9) Remove the exposed seed layer material to expose underlying        portions of the adhesion layer material.    -   (10) Remove exposed portions of the adhesion layer material, for        example, by etching such that the portion of the substrate where        sacrificial material is to exist is exposed as well as edges of        the adhesion layer material and seed layer material and side        walls of the structural material and outward facing surfaces of        the structural material.    -   (11) Apply a second adhesion layer material to the exposed        surfaces. The application of the second adhesion layer material        may be by sputtering or by other appropriate means. The second        adhesion layer material may be the same as the initially applied        adhesion layer material. For example they both may be titanium,        they both may be chromium, the first may be titanium and the        second may be titanium tungsten or vice versa.    -   (12) After application of the adhesion layer material apply a        second seed layer material which may be the same or different        from the first applied seed layer material.    -   (13) Deposit a sacrificial material to at least the regions to        be occupied by sacrificial material (i.e. in the void regions in        the patterned deposit of structural material). The sacrificial        material may be deposited by electroplating and is preferably        deposited to achieve a net thickness at least as great as the        layer thickness and more preferably is at least as great as the        layer thickness plus O.    -   (14) Trim the deposited materials to a height corresponding to        that of the layer thickness so as to complete formation of the        first layer.    -   (15) Add one or more additional layers as appropriate to        complete formation of the structure.    -   (16) Remove the sacrificial material from the structure, for        example, by etching so as to expose or even remove the second        seed layer material.    -   (17) If not removed by the operation of step 16, remove the        second seed layer material, for example, by etching.    -   (18) Remove the second adhesion layer material, for example, by        etching to complete formation of a released structure where        separated portions of the structure are conductively decoupled        from one another.

As noted above with regard to embodiment 6 the two seed layer materialsmay be the same or different and/or the two adhesion layer materials maybe the same or different.

In still further embodiments additional materials may be added to theseed layer stacks. For example, in one alternative the structuralmaterial may be nickel, the sacrificial material may be copper, thefirst adhesion layer material may be titanium, and the first seed layermaterial may be gold while the second adhesion layer material istitanium tungsten and the second seed layer material may be copper (e.g.applied by sputtering). In such an alternative the titanium and titaniumtungsten adhesion layers are preferably very thin, for example, between100 angstroms and 1000 angstroms in thickness and the seed layermaterials may have somewhat greater thicknesses, for example, on theorder of 0.1 microns to 1.5 microns. Most preferably the adhesion layerthicknesses are on the order of 300 to 500 angstroms and the seed layerthicknesses are on the order of 0.3 to 0.7 microns.

Of course in other alternative embodiments thinner or thicker adhesionlayers are possible. One advantage to the choice of adhesion layermaterials and seed layer materials in this alternative is that theetchant for the sacrificial material (e.g. C-38) will not only removethe sacrificial material but will also remove the second seed layermaterial (i.e. copper) and the second adhesion layer material (i.e.Ti—W) but will not significantly attack the first adhesion layermaterial regardless of the fact that it is very thin and sandwichedbetween structural material and the substrate.

FIGS. 11A-11K provide schematic illustrations of side views at variousstages of an example of the process of the sixth embodiment of theinvention.

FIG. 11A depicts a state of the process after a supplied substrate 352has received an adhesion layer 354 (e.g. titanium) and a seed layermaterial 356 (e.g. gold).

FIG. 11B depicts a state of the process after a masking material 358(e.g. patterned photoresist) has been patterned to have openings 360exposing selected portions of seed layer 356 where the openings inmasking material 358 correspond to locations on the seed layer wheresacrificial material is to be deposited.

FIG. 11C depicts a state of the process after deposition of asacrificial material 362 on the exposed portions of seed layer material356.

FIG. 11D depicts a state of the process after mask material 358 has beenremoved revealing openings or voids 364 in the sacrificial material 362.

FIG. 11E depicts a state of the process after the blanket deposition ofa structural material 366.

FIG. 11F depicts a state of the process after the deposits of materialhave been planarized to a height slightly above the level associatedwith layer thickness LT.

FIG. 11G depicts a state of the process after sacrificial material hasbeen removed according to operation 8 as discussed above.

FIG. 11H depicts a state of the process after the exposed portion of theseed layer material and exposed portions of the adhesion layer materialhave been removed to expose portions of substrate 352 where sacrificialmaterial is to exist.

FIG. 11I shows a state of a process after an adhesion layer of a secondadhesion layer material 368 has been deposited and a seed layer ofsecond seed layer material 372 has been deposited.

FIG. 11J depicts a state of the process after the blanket re-depositionof a sacrificial material 362.

FIG. 11K depicts a state of the process after planarization of thedeposited materials to a height equal to that of the layer thickness.After formation of any additional layers the sacrificial material 362may be removed via etching and therewith or thereafter seed layermaterial 372 may be removed and therewith or thereafter adhesion layermaterial 368 may be removed while doing little or no significant damageto the structural material 366, seed layer material 356, or adhesionlayer material 354.

A seventh embodiment of the invention provides a process similar to thatof the sixth embodiment of the invention with the exception that thestructural material for the first layer is deposited prior to anydeposition of sacrificial material. The process flow for the seventhembodiment includes the following operations:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply an adhesion layer of a first material to the        dielectric substrate and then apply a seed layer of a first seed        layer material to the adhesion layer.    -   (3) Mask the substrate using a pattern that leaves the seed        layer exposed in those areas where a structural material is to        be deposited.    -   (4) Electroplate the structural material onto the exposed        portions of the seed layer.    -   (5) Remove the masking material.    -   (6) Remove exposed portions of the first seed layer material.    -   (7) Remove exposed portions of the first adhesion layer        material.    -   (8) Apply an adhesion layer of a second adhesion layer material        to the exposed portions of the substrate to the side walls of        the adhesion and seed layer materials located below the        structural material, the side walls of the structural material        itself, and to the outward facing surface of the structural        material.    -   (9) Apply a seed layer of a second seed layer material to the        surface of the second adhesion layer material.    -   (10) Electroplate sacrificial material over the second seed        layer material such that the deposition thickness of the        sacrificial material brings the minimum height of deposition to        that of the layer thickness or more preferably to something        equal to or greater than the layer thickness plus an incremental        amount.    -   (11) Planarize the deposited materials at a level corresponding        to the height of the first layer.    -   (12) Add additional layers as desired to complete formation of        the structure.    -   (13) Remove the sacrificial material, for example, by etching,        and potentially remove the second seed layer material and the        second adhesion layer material using the same etching operation.    -   (14) Remove the second seed layer material if not already done        so in operation 13.    -   (15) Remove the second adhesive layer material (i.e. from        exposed regions of material if not already done so in operations        13 or 14) so as to complete formation of the released structure        where separate components of the structure are conductively        isolated from one another.

FIGS. 12A-12I provide schematic illustrations of side views at variousstages of an example of the process of the seventh embodiment of theinvention.

FIG. 12A depicts a state of the process where an initial substrate 382is provided which includes a coating of an adhesion layer 384 and a seedlayer 386.

FIG. 12B shows a state of the process after a patterned mask has beenapplied to the surface where openings in the mask leave selected areasof the seed layer 386 exposed and where the selective areas correspondto regions where, as depicted in FIG. 12C, structural material 390 isdeposited within the openings of mask material 388.

FIG. 12D depicts a state of the process after the masking material 388has been removed. The removal of the masking material reveals voids 392where a sacrificial material is to be deposited

FIG. 12E depicts a state of the process after exposed portions of seedlayer material 386 have been removed and voids 392 have been extended indepth.

FIG. 12F depicts a state of the process after exposed regions of thefirst adhesion layer material have been removed thereby extending theheight of voids 392 all the way down to substrate 382.

FIG. 12G depicts a state of the process after a second adhesion layer ofa second adhesion layer material 394, and deposition of a second seedlayer of a second seed layer material 396 are deposited over thesubstrate and all previous depositions located thereon.

FIG. 12H depicts the state of the process after a sacrificial material398 has been blanket deposited.

FIG. 12I depicts a state of the process after the deposits have beenplanarized to a height of one layer thickness LT.

As with the sixth embodiment, additional layers may be deposited on thefirst layer as desired and then after completion of a layer formationsacrificial material 398 may be removed, simultaneously or thereafterthe second seed layer may be removed, and simultaneously or thereafterthe second adhesion layer material may be removed. It is worth notingthat in the sixth and seventh embodiments the second seed layer materialdoes not directly contact the first seed layer material or the firstadhesion layer material and in fact is completely shielded from them bya barrier of the second adhesion layer material.

In implementation where the second adhesion layer material is notattacked by the process or etchant that removes the second seed layermaterial, the first adhesion layer material and the first seed layermaterial will remain protected and thus these first adhesion and seedlayer materials may actually be materials that would be attacked by theetchants or processes that remove the sacrificial material or the secondseed layer material. In other words, in some implementations the blanketdeposition of the second adhesion layer material may act as an etchingbarrier protecting what is below it.

Similarly the blanket deposition of the second seed layer material mayact as a barrier layer protecting what is below it from any attack byetchants or processes used to remove the sacrificial material.

Turning back to FIG. 5D, block 150 sets forth the fourth implementationexample which calls for the removal of both seed layer and adhesionmaterials after deposition of a structural material and then thedepositing of a seed layer material in the regions where a sacrificialmaterial is to be deposited.

An example of this implementation is set forth in an eighth embodimentof the invention which includes the following operations:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply an adhesion layer and a seed layer to the dielectric        substrate.    -   (3) Locate a patterned mask on the surface of the substrate        wherein the patterned mask provides openings that leave those        regions of the substrate that are intended to receive structural        material exposed.    -   (4) Plate the structural material.    -   (5) Remove the mask from the substrate.    -   (6) Remove exposed regions of the seed layer material (i.e.        defined by locations where a sacrificial material will be        deposited).    -   (7) Remove exposed regions of the adhesion layer material.    -   (8) Deposit a second and different seed layer material.    -   (9) Deposit a sacrificial material, for example, by        electroplating.    -   (10) Complete formation of the first layer by planarizing the        deposits to a height corresponding to the layer thickness of the        first layer of the structure.    -   (11) Form any additional desired layer or layers necessary to        complete formation of the layers of the structure.    -   (12) Remove the sacrificial material, for example, by etching,        and potentially remove the second seed layer material and        potentially remove exposed regions of the adhesion layer        material.    -   (13) If not already done so in step 12, remove the second seed        layer material, for example, by etching.    -   (14) If not already done in operations 12 or 13, remove exposed        regions of the adhesion layer material to yield a completed        structure where separate regions of the structure are        conductively isolated from one another.

In a variation of embodiment 8, lapping or other planarizationoperations may occur between operations 4 and 5. Numerous otheralternatives to this and the other embodiments disclosed herein will beapparent to those of skill in the art upon review of the teachingsherein. Furthermore those of skill in the art will understand thatadditional operations may be performed during the practice of thevarious embodiments set forth herein. For example, it will be understoodthat cleaning operations, activation operations, process monitoringoperations, and the like may be performed as necessary.

FIGS. 13A-13M provide schematic illustrations of side views at variousstages of the process of an example of an eighth embodiment of theinvention which provides a second implementation of the example of block150 of FIG. 5D.

FIG. 13A depicts a state of the process after a dielectric substrate 402has been supplied while FIG. 13B depicts a state of the process after anadhesion layer 404 and a seed layer 406 have been adhered to substrate402.

FIG. 13C depicts a state of the process after a patterned mask 408 hasbeen located on the surface of seed layer 406 where openings 410 and themask pattern leave those portions of the seed layer 406 exposed where astructural material is to be deposited.

FIG. 13D depicts a state of the process after a structural material 412has been deposited in openings 410.

FIG. 13E depicts a state of the process after mask material 408 has beenremoved and voids 414 in the structural material 412 revealed.

FIG. 13F depicts a state of the process after exposed portions of seedlayer 406 are removed thereby causing voids 414 to grow deeper in depth.

FIG. 13G depicts a state of the process after exposed portions ofadhesion layer 404 are removed thereby exposing the surface of substrate402.

FIG. 13H represents a state of the process after a second seed layermaterial 416 has been deposited over the exposed regions of thesubstrate, the exposed sidewalls of the structural material, as well asthe outward facing surface of the structural material.

FIG. 13I depicts a state of the process after a blanket deposition of asacrificial material 418 has occurred.

FIG. 13J depicts a state of the process after a trimming operation whichdiminishes the height of the deposited materials to a levelcorresponding to the layer thickness of the first layer of thestructure.

FIG. 13K depicts a state of the process after formation of a secondlayer over and adhered to the first layer.

FIG. 13L depicts the state of the process after removal of sacrificialmaterial 418 leaving all portions of structural material 412conductively connected via seed layer 416.

FIG. 13M depicts the state of the process after removal of seed layer416 which yields the released structure comprised primarily ofstructural material 412 which is attached to substrate 402 via seedlayer 406 and adhesion layer 404 wherein separate portions of structure412 are conductively isolated from one another.

FIG. 5E provides a block diagram indicating three implementationsassociated with the second example implementation of FIG. 5B where twoalternatives for the third implementation are given.

Block 154 of FIG. 5E provides a first implementation example for theprocess of block 152. In this example adhesion layer material is made tocover the substrate. A first seed layer material is deposited overstructural material regions and structural material is deposited, then asecond seed layer material is deposited over the sacrificial materialregion and then a sacrificial material is deposited.

A ninth embodiment of the invention provides more explicit processoperations associated with the example of block 154. Operationsassociated with the ninth embodiment of the invention include:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply an adhesion layer material across the surface of the        substrate.    -   (3) Apply a patterned mask or pattern a mask applied to the        surface of the adhesion layer material where openings in the        mask expose regions of the adhesion layer material where a        structural material is to be deposited.    -   (4) Apply a seed layer material to the exposed regions of the        adhesion layer material, to the side walls of the mask material,        and to the outward facing surface of the mask material. The        selected seed layer material should be appropriate for use with        the structural material.    -   (5) Electroplate a structural material onto the seed layer        material within the openings in the mask.    -   (6) Planarize the surface of the deposited materials and mask        material at a height slightly greater than that of the layer        thickness.    -   (7) Remove the mask from the substrate.    -   (8) Deposit a second seed layer material in the voids in the        structural material exposed by the removal of the mask. In some        variations of this embodiment the second seed layer material may        be deposited on the side walls of the structural material as        well as on the outward facing surface of the structural        material. In other variations the locations where the second        seed layer material is deposited may be more restricted.    -   (9) Deposit a sacrificial material so that it occupies the voids        in the structural material such that the minimum height of        deposition as equal to or preferably greater than the layer        thickness and even more preferably equal to or greater than an        incremental amount δ above the layer thickness level.    -   (10) Planarize the deposited materials to complete formation of        a first layer of the structure.    -   (11) As appropriate add additional layers of material to the        structure.    -   (12) Remove the sacrificial material, for example, by etching        and potentially simultaneously remove the second seed layer        material and potentially even exposed regions of the adhesion        layer material.    -   (13) If not already removed by operation 12, remove the second        seed layer material, for example, by etching.    -   (14) If not already removed by operations 11 or 12, remove        exposed regions of the adhesion layer material to yield a        released structure where separated portions of the structure are        conductively isolated from one another.

FIGS. 14A-14N provide schematic illustrations of side views at variousstages of the process of a ninth embodiment of the invention as appliedin a specific example.

FIG. 14A depicts a state of the process after a substrate 422 isprovided while FIG. 14B depicts a state of the process after substrate422 has received an adhesion layer 424.

FIG. 14C depicts a state of the process after a mask 428 has beenpatterned on adhesion layer 424 leaving voids 430 that expose portionsof the adhesion layer material 424.

FIG. 14D depicts a state of the process after deposition of a seed layermaterial 426 locates seed layer material over the exposed portions ofthe adhesion layer material 424, along the side walls of mask 428, andalong the top surface or outward facing surface of mask 428.

FIG. 14E shows the state of the process after blanket deposition of astructural material 432 deposits material into the voids 430 as well asabove the outward facing surface of mask 428.

FIG. 14F shows the state of the process after the deposited materialsare planarized to a height which is greater than the layer thickness byat least an incremental amount δ. This planarization operation exposesmask material 428 by trimming of the top portions of structural material432 and seed layer material 426.

FIG. 14G depicts a state of the process after masking material 428 isremoved, thus exposing voids 434 in the structural material.

FIG. 14H depicts a state of the process after a second seed layermaterial 436 is deposited over the exposed regions of adhesion layer424, side walls of the structural material (which are already coatedwith the first seed layer material), and the upper surface of structuralmaterial 432.

FIG. 14I depicts a state of the process after blanket deposition of asacrificial material 438 fills the voids 434 and coats over the uppersurface of seed layer material 436 located on structural material 432.

FIG. 14J depicts a state of the process after the first layer ofstructure is completed by the planarization of the deposited materialsto a height corresponding to the layer thickness LT.

FIG. 14K depicts a state of the process after formation of a secondlayer of conductive structural and sacrificial materials is formed.

FIG. 14L depicts a state of the process after sacrificial material 438is removed which yields a partially released structure of desiredconfiguration consisting primarily of structural material 432 but wherethe second seed layer material and the adhesion layer materialconductively connect otherwise separate elements of the structuretogether.

FIG. 14M depicts a state of the process after the second seed layermaterial 436 is removed while FIG. 14N depicts the state of the processafter exposed regions of adhesion layer material 424 have been removed.

Block 156 of FIG. 5E sets forth an implementation of the process ofblock 152 that defines an implementation similar to but opposite to thatset forth in block 154. In particular, in block 156 an adhesion layermaterial covers the substrate as it did in block 154, but an initiallyapplied seed layer coats the adhesion layer in regions where asacrificial material is to be located as opposed to a structuralmaterial as called for in block 154. The process of block 156 continueswith the deposition of sacrificial material followed by the depositionof a second seed layer material in regions where a structural materialis to be deposited and then by the deposition of the structural materialitself.

The process of block 156 is implemented in a tenth embodiment of theinvention which includes the following basic operations:

-   -   (1) Supply a dielectric substrate.    -   (2) Apply an adhesion layer material across the surface of the        substrate.    -   (3) Apply a patterned mask to the substrate or alternatively,        apply a masking material to the substrate and pattern it such        that openings in the mask material leave portions of the        adhesion layer material exposed where a sacrificial material is        to be deposited.    -   (4) Apply a first seed layer material to the regions to be        occupied by sacrificial material. The application of the seed        layer material may result in its deposition not only to the        exposed surfaces of the adhesion layer material but also to the        surfaces of the mask material.    -   (5) Electroplate sacrificial material onto the seed layer        covered portions of the adhesion layer material. The deposition        of the sacrificial material may also cause sacrificial material        to be deposited on the seed layer material covering the mask        material.    -   (6) Planarize the deposited materials and mask materials to a        height that is equal to or greater than the layer thickness plus        an incremental amount.    -   (7) Remove the mask material. For example, if the mask material        is a photoresist material, remove it using a standard stripping        process.    -   (8) Deposit a second seed layer material into void regions in        the sacrificial material which were exposed by the removal of        the mask material. These void regions represent regions where a        conductive structural material is to be deposited. The        deposition of the seed layer material may or may not result in        seed layer material covering the walls and outward facing        surface of the deposited sacrificial material.    -   (9) Deposit the structural material into the void regions where        a minimum height of deposition is preferably greater than or        equal to the layer thickness plus an incremental amount. The        incremental amount may be an amount that is greater than or        equal to a tolerance associated with the planarization        operations that are used in setting layer levels and the like.    -   (10) Planarize the surface of the deposited materials such that        a height corresponding to the layer thickness is achieved so as        to complete formation of the first layer of the structure.    -   (11) Form one or more additional layers as appropriate to        complete formation of the structure.    -   (12) Remove the sacrificial material, for example, by etching,        and potentially simultaneously remove the second seed layer        material and potentially even exposed regions of the adhesion        layer material.    -   (13) If not already removed by operation 12, remove the second        seed layer material, for example, by etching.    -   (14) If not already removed by operations 11 or 12, remove        exposed regions of the adhesion layer material to yield a        released structure where separated portions of the structure are        conductively isolated from one another.

FIGS. 15A-15N provide schematic illustrations of side views at variousstages of the process of a tenth embodiment of the invention as appliedin a specific example.

FIG. 15A depicts the state of the process after a substrate 442 has beensupplied.

FIG. 15B depicts a state of the process after an adhesion layer material444 is deposited on substrate 442.

FIG. 15C depicts a state of the process after a patterned mask material448 is located on the adhesion layer 444. Openings 450 exist in maskmaterial 448 and represent locations where sacrificial material is toexist on the first layer of the structure.

FIG. 15D depicts a state of the process after a seed layer material 446is applied to the exposed regions of adhesion layer material 444 and toexposed surfaces of mask material 448.

FIG. 15E depicts a state of the process after blanket deposition of asacrificial material 452 causes the sacrificial material to be locatedin voids 450 as well as over the seed layer material 446 that is locatedon the mask material 448.

FIG. 15F depicts a state of the process after a planarization operationtrims the deposit heights to a level just above that associated with adesired layer thickness for the first layer.

FIG. 15G depicts a state of the process after mask material 448 has beenremoved and portions of adhesion layer 444 are exposed and voids 454 inthe sacrificial material are revealed.

FIG. 15H depicts a state of the process after a second seed layermaterial 456 is deposited onto the exposed regions of adhesion layer 444as well as on side walls and outward facing surfaces of sacrificialmaterial 452.

FIG. 15I depicts a state of the process after a blanket deposition ofstructural material 458 causes structural material to fill the voids 454to a minimum height equal to the layer thickness plus an incrementalamount.

FIG. 15J depicts a state of the process after the formation of the firstlayer of the structure is completed as a result of a planarizationoperation which trims the height of the depositions to that of the layerthickness.

FIG. 15K depicts a state of the process after a second layer has beendeposited and adhered to the first layer.

FIG. 15L depicts a state of the process after sacrificial material 452has been removed.

FIG. 15M depicts a state of the process after removal of the first seedlayer material 446.

FIG. 15N depicts a state of the process after removal of exposed regionsof adhesion layer 444 which results in completion of the structure whereseparate regions of the structure are conductively isolated from oneanother.

Block 162 of FIG. 5E specifies a third more detailed implementation ofthe process of block 152 wherein a seed layer material is applied onlyto regions where sacrificial material will be deposited while regionswhere a structural material is to be located will receive a nickeldeposit via a nickel strike operation.

Blocks 164 and 166 provide two alternative examples of how the processof block 162 might be implemented.

Block 164 calls for the deposition of the structural material prior todeposition of sacrificial material while block 166 calls for thedeposition of sacrificial material prior to that of structural material.

The approach of block 164 is implemented in an eleventh embodiment ofthe invention which involves the following primary operations:

-   -   (1) Supply a dielectric substrate on which to form a structure.    -   (2) Apply an adhesion layer material across the surface of the        substrate.    -   (3) Form a desired pattern of a masking material on the        substrate such that openings in the mask material leave portions        of the adhesion layer material exposed, and in particular,        portions of the adhesion layer material where a structural        material is to be deposited.    -   (4) Perform a nickel plating strike e.g. a woods strike, on the        exposed portions of the adhesion layer material.    -   (5) Plate structural material over the region that has received        the nickel strike.    -   (6) Remove the mask material. In variations of this embodiment        it may be desirable to planarize the masking material and        structural material prior to removing the mask material but it        is believed not to be necessary as the masking material is not        covered by seed layer material or structural conductive        material.    -   (7) Deposit a second seed layer material (the nickel strike may        be considered the first seed layer material which was        selectively deposited). The second seed layer material is        located on the adhesion layer material in those regions where        the mask material was removed, while the seed layer may also be        deposited onto the side walls of the structural material as well        as on the outward facing surface of the structural material.    -   (8) Next sacrificial material is deposited to fill the voids in        the structural material where the minimum height of deposition        is preferably greater than the layer thickness plus an        incremental amount.    -   (9) Planarize the deposited material at a level corresponding to        the thickness of the first layer.    -   (10) Add one or more additional layers to complete build up of        the layers of the structure.    -   (11) Form one or more additional layers as appropriate to        complete formation of the structure.    -   (12) Remove the sacrificial material, for example, by etching        and potentially simultaneously remove the second seed layer        material and potentially even exposed regions of the adhesion        layer material.    -   (13) If not already removed by operation 12, remove the second        seed layer material, for example, by etching.    -   (14) If not already removed by operations 11 or 12, remove        exposed regions of the adhesion layer material to yield a        released structure where separated portions of the structure are        conductively isolated from one another.

The approach of block 166 is implemented in a twelfth embodiment of theinvention which includes the following major operations:

-   -   (1) Supply a dielectric substrate on which the structure is to        be formed.    -   (2) Apply an adhesion layer material across the surface of the        substrate.    -   (3) Locate patterned masking material on the substrate so as to        leave regions of the adhesion layer material exposed where        sacrificial material is to be deposited.    -   (4) Apply a first seed layer material to the exposed regions of        the adhesion layer material as well as to the side walls and        outward facing surface of the masking material.    -   (5) Plate sacrificial material onto the first seed layer        material such that a minimum height of deposition in the open        regions of the mask reach or exceed the layer thickness plus an        incremental amount.    -   (6) Planarize the masking material and the deposited materials        to a height equal to the layer thickness plus an incremental        amount.    -   (7) Remove the mask material to expose portions of the adhesion        layer material where a sacrificial material is to be deposited.    -   (8) Perform a nickel strike on the exposed surfaces of the        adhesion layer material to form an appropriate seed layer so        that electroplated nickel may be received.    -   (9) Electrodeposit the structural material onto the region that        received the nickel strike such that a minimum height of        deposition equals or exceeds that of the layer thickness and        more preferably the layer thickness plus an incremental amount.    -   (10) Planarize the deposited materials to achieve a net height        equal to that of the layer thickness.    -   (11) Form one or more additional layers as appropriate to        complete formation of the structure.    -   (12) Remove the sacrificial material, for example, by etching        and potentially simultaneously remove the second seed layer        material and potentially even exposed regions of the adhesion        layer material.    -   (13) If not already removed by operation 12, remove the second        seed layer material, for example, by etching.    -   (14) If not already removed by operations 11 or 12, remove        exposed regions of the adhesion layer material to yield a        released structure where separated portions of the structure are        conductively isolated from one another.

FIGS. 16A-16M provide schematic illustrations of side views at variousstages of the process of an eleventh embodiment of the invention asapplied to the formation of a particular structure.

FIG. 16A depicts a state of the process after a substrate 462 has beensupplied.

FIG. 16B depicts a state of the process after substrate 462 has receivedan adhesion layer 464.

FIG. 16C depicts a state of the process after a masking material 468 hasbeen applied to the surface of adhesion layer material 464. Openings 470in mask material 468 correspond to locations where a structural materialis to be deposited.

FIG. 16D depicts a state of the process after a nickel deposit 466 coatsthe exposed portions of adhesion layer material 464.

FIG. 16E depicts a state of the process after electrodeposition ofstructural material 472 is deposited onto nickel strike material 466.

FIG. 16F depicts a state of the process after mask material 468 isremoved which reveals voids 474 in structural material 472.

FIG. 16G depicts a state of the process after a second seed layermaterial 476 is deposited onto adhesion layer 464 and onto the sidewalls and outward facing surface of structural material 472.

FIG. 16H depicts a state of the process after a blanket deposition ofsacrificial material 478 results in sacrificial material filling thevoids 474 in the structural material.

FIG. 16I depicts a state of the process after the first structural layeris completed by a planarization operation which trims the height of thedeposits to correspond to that of the desired layer thickness.

FIG. 16J depicts a state of the process after a second layer of materialhas been formed above the first layer of material.

FIG. 16K depicts a state of the process after sacrificial material 478has been removed.

FIG. 16L depicts a state of the process after seed layer material 476has been removed.

FIG. 16M depicts a state of the process after exposed regions ofadhesion layer material have been removed.

FIGS. 17A-17N provide schematic illustrations of side views at variousstages of the process of a twelfth embodiment of the invention asapplied to the formation of a particular structure.

FIG. 17A depicts a state of the process after the substrate 482 isreceived whereas FIG. 17B depicts the state of the process after anadhesion layer material 484 is deposited on the substrate.

FIG. 17C depicts a state of the process after a patterned maskingmaterial 488 is formed on the surface of adhesion layer 484. Openings490 through masking material 488 expose regions of adhesion layer 484where a sacrificial material is to be deposited.

FIG. 17D depicts a state of the process after a first seed layermaterial 486 is deposited onto the exposed portions of the adhesionlayer and also on the outward facing surface of the masking material.

FIG. 17E depicts a state of the process after a sacrificial material 492is electroplated onto the seed layer material 486 so that a minimumheight of deposition preferably greater than or equal to the layerthickness plus an incremental amount is formed in regions of voids 490.

FIG. 17F depicts the state of the process after the deposited materialsand masking material are planarized to a height that is preferablygreater than or equal to the layer thickness plus an incremental amount.

FIG. 17G depicts a state of the process after masking material 488 isremoved.

FIG. 17H depicts a state of the process after a nickel strike depositsnickel seed layer material 494 in void regions 496 exposed by theremoval of masking material 488. The nickel seed layer material isdeposited to regions where a structural conductive material is to bedeposited.

FIG. 17I depicts a state of the process after structural material 498 isdeposited to fill voids 496 such that the minimum height of depositionlocates the surface of the structural material at a height equal to orgreater than the layer thickness plus an incremental amount δ.

FIG. 17J depicts a state of the process after the deposited materialshave been planarized to a thickness equal to the layer thickness.

FIG. 17K depicts a state of the process after a second layer of materialhas been added.

FIG. 17L depicts a state of the process after the sacrificial materialhas been removed while FIG. 17M depicts the state of the process afterthe first seed layer material 486 is removed.

FIG. 17N depicts a state of the process after exposed adhesion layermaterial has been removed.

FIG. 5F provides a block diagram indicating a more detailedimplementation example (along with two alternatives therefore)associated with the fourth example implementation of FIG. 5B.

Block 174 provides a more detailed description of a particularimplementation of the process of block 172. In particular, block 174calls for the use of a patterned material to define initial regions onthe substrate where the first seed layer stack and first selectedmaterial of block 172 will be deposited and then to use the first seedlayer stack and first selected material as the mask for defining regionsthat will receive a second seed layer stack and the second material.

Blocks 176 and 178 provide examples of two variations of the process ofblock 174 which may be used in its implementation (in particular block176) that in situations where the seed layer material of the first andsecond seed layer stacks are the same, then removal of the seed layermaterial associated with the sacrificial material may occur withoutdamaging the seed layer material for the structural material by insuringthat structural material deposited on the second layer completely coversthe boundary regions separating the structural and sacrificial materialson the first layer.

Block 178 is directed to situations where the seed layer material forthe first and second seed layer stacks are different and where thesacrificial material and the associated seed layer material and adhesionlayer material can be separated from the seed layer material andadhesion layer material associated with the structural material withoutdamaging them. In these circumstances block 178 indicates that there areno restrictions on the design of the second layer relative to the firstlayer.

Embodiment thirteen of the present invention provides a detailed processfor an example implementation of the approach of block 176 whereasembodiment fourteen provides a detailed process that may be used inimplementing the approach of block 178 of FIG. 5F.

Primary operations associated with the thirteenth embodiment of theinvention include:

-   -   (1) Supply a dielectric substrate.    -   (2) Pattern a material, for example a photoresist, on the        surface of the substrate leaving voids where a first of the        sacrificial material or structural material is to be located.    -   (3) Apply a first adhesion layer material and a first seed layer        material to the exposed surfaces of the substrate as well as to        its sidewalls and outward facing surface of the masking        material.    -   (4) Deposit a first of the sacrificial material or structural        materials onto the seed layer stack located on the substrate        such that a desired minimum height of deposition is achieved.        For example, the minimum height of deposition may be set to an        amount equal to or greater than the layer thickness plus an        incremental amount.    -   (5) Planarize the deposited material and mask material to a        height corresponding to the layer thickness plus an incremental        amount.    -   (6) Remove the masking material from the substrate thereby        exposing regions of the substrate where a second of the        structural material or sacrificial material is to be located.    -   (7) Deposit a second adhesion layer material and second seed        layer material onto the substrate in the regions where the        masking material was removed and also onto the sidewalls of the        deposited materials associated with the first of the structural        or sacrificial material and onto the outward facing surface of        that first material.    -   (8) Deposit the other of the sacrificial material or structural        material such that the minimum depth of the deposition meets or        exceeds that of the layer thickness plus an incremental amount.    -   (9) Planarize the deposits of the materials to a height        corresponding to the layer thickness of the first layer of the        structure.    -   (10) Add additional layers as desired wherein the structural        material deposited on the second layer preferably overlays the        boundary regions separating the structural materials from the        sacrificial materials. More specifically in some preferred        embodiments the structural material on the second layer will        overlay not only the structural material on the first layer but        will also overlay the associated seed layer material and        adhesion layer material.

In other variations the structural material on the second layer maysimply overhang the structural material on the first layer and the seedlayer material on the first layer or at least a large portion of theseed layer associated with structural material on the first layer suchthat any access paths by an etching solution to the seed layer materialassociated with the structural material are sufficiently small that theseed layer material associated with the structural material cannot beremoved or damaged to a significant amount in regions where structuralmaterial adheres to the substrate via the seed layer material.

-   -   (11) Remove the sacrificial material by etching and potentially        remove the seed layer associated with the sacrificial material        in the same etching process.    -   (12) If the seed layer material associated with the sacrificial        material is not removed in operation 11, remove the seed layer        material, for example, by using an etching operation that is        selective to the seed layer material and that does not do damage        to the structural material or to the adhesion layer material        associated with the structural material that acts as an etch        stop for the seed layer material associated with the structural        material.    -   (13) Remove exposed portions of the adhesion layer material        associated with the sacrificial material. This operation may or        may not also attack exposed regions of the adhesion layer        associated with the structural material. If the adhesion layer        material associated with the structural material is attacked,        the thinness of the adhesion layer material in the region        separating the structural material from the substrate should be        thin enough to inhibit significant damage to this sandwiched        adhesion layer material.

In one implementation of the process of embodiment thirteen the adhesionlayer for the sacrificial material may be titanium-tungsten while theseed layer material for the sacrificial material is copper and thesacrificial material itself may be copper. In such an embodiment thestructural material may be nickel and the adhesion layer materialassociated with the structural material may be titanium while the seedlayer material associated with the structural material may be copper orgold or any other material. As a seed layer of titanium-tungsten may bereadily attacked by the etchant used to remove a copper sacrificialmaterial, the use of an adhesion layer of titanium for the structuralmaterial may have a benefit in that the etchant for the copper will notreadily attack pure titanium. And thus there is no worry aboutinadvertent undercutting of the adhesion layer or undercutting of theseed layer associated with the structural material such as a copperbased seed layer material.

In another variation, if the seed layer material or the structuralmaterial is gold, it may be possible to use a titanium-tungsten seedlayer for the structural material even though it may be attacked by theetchant used to remove the sacrificial material as the barrier providedby the gold and the thinness of the adhesion layer material sandwichedbetween the gold and the substrate may ensure that no significant damageoccurs to the structural integrity of the structure where it is mountedto the substrate.

A fourteenth embodiment of the invention offers more freedom of designas the second layer of structural material can take on any appropriateconfiguration without worrying about it having to function as a cappinglayer to protect the seed layer material associated with the structuralmaterial.

In the fourteenth embodiment it is necessary that the seed layerassociated with the structural material not be attacked by any etchantsthat it may come into contact with. For example, it should not beattacked, at least aggressively, by the etchant used to remove thesacrificial material. It should also not be attacked by an etchant usedto remove the seed layer material associated with the sacrificialmaterial. For example, if the sacrificial material is copper and itsseed layer is copper then a seed layer of gold or tin or silver would beeffective for the structural material in this embodiment. It is alsopreferred that the adhesion layer material used for the structuralmaterial not be attacked by etchants used to remove the sacrificialmaterial, the associated seed layer material, or the associated adhesionlayer material. In particular, if the sacrificial material is copper andthe associated seed layer material is copper and the associated adhesionlayer material is titanium-tungsten, all may be etched by the sameetchant whereas use of a titanium seed layer for the structural materialwould be appropriate in this embodiment as it would probably not besignificantly attacked by the etchant of choice. It will be understoodby those of skill in the art that other material combinations will bepossible and that if necessary, minimum experimentation could beperformed to distinguish working material and etchant combinations fromnon-working combinations.

FIGS. 18A-18L provide schematic illustrations of side views at variousstages of the process of a thirteenth embodiment of the invention asapplied to the formation of a specific exemplary structure.

FIG. 18A depicts a state of the process after a substrate 502 isapplied.

FIG. 18B depicts a state of the process after a patterned maskingmaterial 500 is formed on substrate 502 where voids 510 exist in themasking material, which define regions to be occupied by structuralmaterial or sacrificial material. In this embodiment it is assumed thatthe first material to be deposited will be structural material and assuch the various operations of this embodiment will reflect that choice.It will be understood by those of skill in the art that alternativeembodiments may utilize the sacrificial material as the first depositedmaterial.

FIG. 18C depicts a state of the process after an adhesion layer 504associated with the structural material is deposited, a seed layer 506associated with the structural material is deposited and the structuralmaterial itself 508 is deposited. The minimum height of depositionassociated with the structural material is equal to or greater than thelayer thickness plus an incremental amount which will allow anynecessary amount to accommodate tolerances in planarization.

FIG. 18D depicts a state of the process after the masking material andstructural materials have been planarized to a level that is somewhathigher than the ultimate desired layer thickness.

FIG. 18E depicts a state of the process after masking material 500 hasbeen removed leaving adhesion layer material 504, seed layer material506 and conductive structural material 508. FIG. 18E also depicts voids514 in the deposited structural materials. The voids represent regionsto be occupied by sacrificial material.

FIG. 18F depicts a state of the process after an adhesion layer 524 anda seed layer 526 associated with a sacrificial material have beendeposited into the exposed regions of substrate 502 in preparation forreceiving a deposit of sacrificial material.

FIG. 18G depicts a state of the process after sacrificial material 512has been deposited to fill voids 514.

FIG. 18H depicts a state of the process after the formation of the firstlayer is completed as the result of a planarization operation that setsthe thickness of the deposits equal to the layer thickness.

FIG. 181 depicts a state of the process where a second layer is formedabove and adhered to the first layer and wherein structural materialregions 508 on the second layer overlay the boundary regions separatingthe structural materials and the sacrificial materials of the firstlayer.

FIG. 18J depicts a state of the process after sacrificial material 512has been removed.

FIG. 18K depicts a state of the process after seed layer 526 associatedwith the sacrificial material 512 has been removed.

FIG. 18L depicts two alternative versions of potential states of theprocess after adhesion layer 524 is removed. The left most figure ofFIG. 18L assumes that the removal of adhesion layer 524 does not attackthe side walls of adhesion layer 504 and thus the adhesion layer remainsin place. The right most figure of FIG. 18L depicts the state of theprocess under the circumstance where the removal of adhesion layer 524also results in the removal of exposed regions of adhesion layer 504 butnot significant removal of adhesion layer material 504 located betweenthe substrate and seed layer 506.

FIGS. 19A-19D provide schematic illustrations of side views at variousstages of the process of a fourteenth embodiment of the invention asapplied to the formation of a specific exemplary embodiment.

FIG. 19A depicts a state of the process after formation of a first andsecond layer have been completed where the first and second layersinclude structural material 508 and sacrificial material 512. The firstlayer also includes adhesion layer material 504 and seed layer material506 as well as adhesion layer material 524 associated with thesacrificial material and seed layer material 526 also associated withthe sacrificial material.

FIG. 19B depicts a state of the process after removal of sacrificialmaterial 512 where it can be seen that the structural materialassociated with the first and second layers do not result in thematerial of the second layer overlaying the boundary interface regionsbetween the structural and sacrificial materials of the first layer. Inparticular, regions 528 indicate that direct pathways to seed layer andadhesion layer materials for the structural materials exist forsacrificial material etchants. But as it is assumed in this embodimentthat such etchants will not attack the seed and adhesion layers or thestructural material, such pathways are not an issue.

FIG. 19C depicts the state of the process after seed layer material 526has been removed.

FIG. 19D depicts a state of the process after adhesion layer 524 hasbeen removed.

FIG. 5G provides a block diagram indicating a more detailedimplementation example (along with two alternatives therefore)associated with the fifth example implementation (block 182) of FIG. 5B.

Block 184 provides an example of a first alternative to the process ofblock 182. The process of block 184 calls for the structural material tohave associated with it an adhesion layer material and a seed layermaterial while the sacrificial material would have associated with it adifferent seed layer material but will not have a separate adhesionlayer material.

Block 186 on the other hand calls for the sacrificial material to haveassociated with it an adhesion layer material and a separate seed layermaterial while the structural material has a different seed layermaterial associated with it but no separate associated adhesion layermaterial.

A fifteenth embodiment of the invention provides a specificimplementation of the process of block 184 of FIG. 5G. In particular theprimary operations associated with the fifteenth embodiment include thefollowing:

-   -   (1) Supply a dielectric substrate.    -   (2) Mask the substrate so that regions of the substrate not to        be covered by structural material are masked while regions to be        covered by structural material remain exposed.    -   (3) Apply an adhesion layer material and a seed layer material        to the substrate, the side walls of the masking material, and to        the outward facing surface of the masking material in        preparation for depositing a structural material.    -   (4) Electrodeposit the structural material such that a minimum        height of deposition is achieved that is equal to or somewhat        greater than the layer thickness plus an incremental amount δ.    -   (5) Planarize the masking material and deposited structural        material to a height corresponding to the layer thickness plus        an incremental amount.    -   (6) Remove the masking material so as to expose portions of the        substrate where a sacrificial material is to be deposited.    -   (7) Deposit a second seed layer material to the exposed regions        of the substrate and to the side walls and outward facing        surface of the structural materials.    -   (8) Electrodeposit the sacrificial material such that a desired        minimum height of deposition preferably greater than or equal to        the layer thickness plus an incremental amount is achieved.    -   (9) Planarize the deposits to a level corresponding to that of        the layer thickness.    -   (10) Add one or more additional layers as desired to complete        the layer formation process.    -   (11) Remove the sacrificial material, for example, by etching        and potentially remove the second seed layer material at the        same time.    -   (12) If not removed in association with operation 11, remove the        second seed layer material, for example, by etching so as to        complete formation of the released structure where separate        elements of the structure are conductively isolated from one        another.

FIGS. 20A-20L provide schematic illustrations of side views at variousstages of the process of a fifteenth embodiment of the invention whichprovides a first implementation of the example of block 184 of FIG. 5H.

FIG. 20A depicts a state of the process after supplying a substrate 542while FIG. 20B depicts a state of the process after forming a desiredpattern of masking material 548 on the substrate.

FIG. 20C depicts a state of the process after application of an adhesionlayer 544 and a seed layer 546 that are associated with a structuralmaterial to be deposited.

FIG. 20D depicts a state of the process after a structural material 552is deposited.

FIG. 20E depicts a state of the process after the materials areplanarized to a height slightly greater than one layer thickness.

FIG. 20F depicts a state of the process after masking material 548 hasbeen removed.

FIG. 20G depicts a state of the process after a second seed layermaterial 554 has been deposited.

FIG. 20H depicts a state of the process after a sacrificial material 556has been deposited while FIG. 20I depicts a state of the process afterthe deposited materials have been planarized to a height of one layerthickness which completes formation of the first layer.

FIG. 20J depicts a state of the process after a second layer has beenadded.

FIG. 20K depicts a state of the process after sacrificial material 556has been removed while FIG. 20L depicts a state of the process after thesecond seed layer material 554 has been removed which completes theprocess and yields a released structure whose separate regions areconductively isolated from one another.

The methods and operations employed in the embodiments of the inventionas discussed above may be applied not only to the forming of the initiallayer of structure when building on a dielectric substrate but they mayalso be applied during the formation of additional layers when theirimmediately preceding layers include a dielectric material. Theembodiments set forth above may be modified to leave or add one or moredielectric materials to the layers being formed. Such modifications maybe based on the teachings set herein explicitly or based on teachingsfrom other patent applications that are incorporated herein byreference. As such, other embodiments of the invention may involve someor all layers of a structure incorporating a dielectric material.Incorporation of dielectric material may occur via the teachings foundherein before and herein after as well as in a number of the patentapplications incorporated herein by reference. In still otherembodiments, more than one structural material may be deposited on agiven layer and/or more than one sacrificial material may exist on agiven layer.

Some embodiments may be directed to the formation of single layerstructures as opposed to multi-layer structures.

In still other embodiments data processing and masking techniques may beused to limit seed layer and/or adhesion layer formation to occur onlyover dielectric material (e.g. on the substrate or previously depositedlayer) or such that it overlays conductive material only slightly suchthat dielectric material is not located between successive layers ofconductive structural material and/or between successive layers ofconductive sacrificial material.

In still other embodiments it may be possible to place seed layermaterial and/or adhesion layer material only over dielectric materialand to leave a zero gap or slight gap between any conductive material onthe substrate or previously formed layer and the seed layer materialwhere such a gap can be readily bridged during plating operations tocause deposited conductive material to overlay the conductive materialregions on the previous layer as well as to overlay seed layer regionson the present layer.

In other embodiments where more than two building materials are to bedeposited, it may be possible to avoid a second patterning operation ofa masking material or to avoid removing, reapplying, and then patterninga second masking material. In such alternative embodiments it may bepossible to initially pattern the dielectric material to form voids thatrepresent the union of the locations where the first and secondconductive materials will be deposited. After which a seed layer for thefirst conductive material may be applied, the first conductive materialmay be applied to fill all voids, and then the deposit(s) may,optionally, be trimmed (e.g. planarized) to a desired level. Next a maskmay be overlaid on the surface of the first conductive material. Voidsmay exist in the mask at the time of mating the masking material to thepreviously deposited materials. Alternatively, the voids may be formedin the masking material after mating has occurred. The mask may, forexample, be of the contact or adhered type. The voids in the maskpreferably correspond to locations where a second conductive material isto be located. Etching of the first conductive material may occur to adesired depth and even exposed seed layer material may be removed (andpotentially other associated materials as well). If the seed layer is tobe removed, it may be removed by the same process (e.g. etchant) as isused for removing the conductive material or alternatively it may beremoved by a different process (e.g. using a different etchant). Next,with or without removing the masking material that was used for etching,the second conductive material may be deposited and if necessary priorto that deposition, a seed layer material or seed layer stack ofmaterials, appropriate for the second conductive material, may bedeposited. After deposition of the second conductive material, the maskmay be removed (if not already removed) and planarization of the surfacemay occur to remove any seed layer material or seed layer stack ofmaterials located above the first conductive material to bring the netlayer height to a thickness equal to that of the intended layerthickness.

In still further embodiments, it may be desirable to not usemechanical-type or machining-type operations (e.g. lapping, machining,milling or the like) to trim seed layer material from the surface of thedielectric or other conductive material which it overlays. In someembodiments etching operations may be used to remove the seed layermaterial. In some alternative embodiments, the etching operations may bedone in a selective manner or in a largely selective manner such thatseed layer material is attacked and removed while causing no more thaninsignificant damage to any deposited conductive material located abovethe seed layer. In other alternative embodiments, the seed layer etchingprocess may also attack the material that was deposited above the seedlayer and/or attack other exposed conductive and/or dielectricmaterials. In such embodiments, the coating thickness of the materialsattacked by the etchant may be such that the etching is insufficient tocause the regions to fall below a desired minimum thickness (e.g. belowa level corresponding to the layer thickness). After the etchingoperations have operated on the seed layer material sufficiently, thedeposited materials may be ready for receiving subsequent deposits andprocessing or alternatively a planarization operation may be used tobring the surface of the deposited material to a desired level. In someembodiments, scratching or otherwise forming openings in the seed layermay be sufficient to allow an etchant (e.g. developer or stripper) toattack the underlying dielectric material (e.g. photoresist) which mayresult in removal of the dielectric as well as removal of any overlyingseed layer material by a lift off process. Such removal via lift off maybe accompanied by ultrasonic agitation or the like.

In additional embodiments, the etching operations set forth above may beused to incorporate additional structural or dielectric materials ofeither the conductive or dielectric type. In some embodiments, theetching operations may be used in such a manner that at any given timeonly one material is being etched into. In other alternatives, etchingoperations may cut into more than one material simultaneously.

In still further embodiments, the orders of applying materials in theabove described embodiments may be modified along with makingappropriate changes to the processes.

The effectiveness of various embodiments and alternatives discussedabove and below may be enhanced by use of one or more of the followingtechniques. Formation of seed layers and/or adhesion layers ondielectric materials may be accomplished using a variety of differentoperations or processes. For example, the formation may occur using asputtering or other PVD or CVD process, an electroless depositionprocess, or via a direct metallization process.

Operations and parameters involved in sputtering processes or other PVDor CVD process are known to those of skill in the art or may be readilyascertained by them without undue experimentation. Electrolessdeposition processes and parameters are also known to those of skill inthe art or may be readily ascertained by them without undueexperimentation. Electroless deposition processes are capable of formingcoatings of many different materials including, for example Au, Ag, Sn,Cu, Ni, and the like. Similarly, direct metallization processes are alsoknown to those of skill in the art or may be readily ascertained by themwithout undue experimentation. Direct metallization processes may beused to deposit different materials including for example Cu and Ni.

For example, an electroless deposition process for copper may involvethe following operations:

-   -   (1) Activate the substrate using a solution of hydrochloric        acid, tin chloride, and palladium chloride where the        concentrations and ratios of each as well as the general process        parameters that may be used are ascertainable or purchasable        from standard sources by those of skill in the art.    -   (2) Optionally, rinse with de-ionized water; and    -   (3) Expose the substrate to an electroless deposition solution        containing sodium hydroxide, formaldehyde, a chelator, and a        copper salt where the relevant concentrations and ratios and        other process parameters are ascertainable or purchasable from        standard sources by those skilled in the art.

The purpose of the direct metallization or direct plating process is toallow electroplating of a conductive layer directly on a non-conductivesubstrate. Three different commercial processes exist for directmetallization: (1) Pd colloidal processes, (2) conductive polymerprocesses, and (3) carbon/graphite based systems. For example, a directmetallization or direct plating process may be implemented via a seriesof steps or operations: (1) First, the substrate is dipped in an etchingsolution to roughen its surface; (2) Then, the substrate is dipped in anactivator solution to get surface conductive; and then; and (3) A verythin (<1 um) metal layer (e.g., Cu, Ni or Au) is plated onto thesubstrate.

For the Pd colloidal process, there are two subgroups: (a) the Pd-Sncolloidal process and (2) the Sn free Pd process. Some examples ofcommercial processes include: (1) Crimson (Shipley), (2) Envision DPS(Enthone), and (3) Compact-1 (Atotech). A typical process flow includescleaning, microetch, activation and plating.

For the conductive polymer processes, examples of commercial processesinclude: (1) DMS-2 (Blasberg Co.) and (2) Compact CP (Atotech). Theconductive polymers include polypyrrole or 3,4 ethlendioxythiophene.

For the carbon processes, examples of commercial processes include (1)Black Hole II (MacDermid), (2) Shadow (Electrochemicals Co.). and (3)Graphite 200 (Shipley).

An important portion of some embodiments of the invention relates to theability to separate sacrificial materials, any associated seed layers,and/or any associated adhesion layer materials from the desiredstructures and from the substrate while doing minimal damage to thestructural material, any associated seed layer materials, and anyassociated adhesion layer materials. The separation of these materialsmay occur after partial or complete formation of a first layer, afterpartial or complete formation of a subsequent layer or after completionof the last layer to be formed.

In some embodiments, a gold (Au) seed layer material and a titaniumadhesion layer material must be separated from the structural materials.In these embodiments, the gold layer generally has a thickness between0.1 and 1.0 microns, more typically between 0.3 and 0.7 microns and mosttypically between about 0.4 and 0.6 microns (-0.5 μm) and the titaniumlayer generally has a thickness between about 50 and 500 angstroms andmore typically about 100 to 300 A. In some embodiments, the gold etchantmay be GE-8148 from Transene Co. Inc. of Danvers, Mass. and the titaniumetchant may be TFTN which is also from Transene Co. Inc.

From the technical datasheet for GE-8148, the etch rate for the goldetchant is about 50 angstroms/second at 25° C. As such, it takes about100 seconds to remove the 0.5 μm (micron) Au seed layer. But since inactual application the gold has a variable layer thickness, the etchrate is variable and it is difficult to control the etch fromover-attacking regions where etching may not be desired while waitingfor the etching to be completed in other areas which may haveinadvertently or intentionally received thicker initial coatings. It isdifficult to control the etching process during such short timeintervals. If the etching is not well controlled, severe undercuttingmay result which may cause yield reductions or complete failures ofprocesses that would have otherwise been successful. To control theprocess, it is desirable to extend the etching time. Such extensions mayinvolve factors of 2, 3, 5, 10 or even higher values. For example, itmay be desirable to extend the etching time so that it takes 10 minutesinstead of 1 minute. Tests have shown that such an extension of time maybe obtained by diluting the concentration of the purchased etchant usingdistilled water. Tests have shown that it takes about 10 minutes toremove Au using a concentration of 1 part full strength etchant to 15parts DI water and about 5 - 7 minutes using a concentration of 1 partfull strength etchant to 10 parts DI water. As such, dilution of bathsbeyond ranges recommended by material suppliers may have significantlybeneficial results.

It has also been observed that in the case of GE-8148, though the vendorhas indicated that the etchant will not attack nickel films, experimentshave shown that such attack does occur when diluted baths are used. Assuch, in some embodiments of the invention, it is desirable to add aneffective quantity of nickel corrosion inhibitor to the bath.

In one test, 1 g NaNO3 per 100 ml of solution was added in a 1:10diluted Au etchant. After etching, no noticeable Ni corrosion was seen.U.S. patent application Ser. No. 10/434,294, by Gang Zhang, entitled“Electrochemical Fabrication Method With Enhanced Post DepositionProcessing” describes the addition of such a corrosion inhibitor toEnstrip C-38 Stripper (Enthone-OMI Inc. of New Haven, Conn.). Thisreferenced patent application is hereby incorporated herein by referenceas if set forth in full. It is possible to use even higherconcentrations, for example 5-10% and still get effective results. Forexample, in another test, 5 g/100 ml NaNO3 was added in 1:10 Au etchantand effective Au etching was obtained without evidence of Ni corrosionbeing observed. In still other embodiments, a smaller concentration maystill yield effective results.

In other embodiments, instead of using NaNO3 as the inhibitor it may bepossible to use ammonium phosphate dibasic or the like.

In still other embodiments, additional steps may be taken to protectstructural material surfaces (e.g. nickel surfaces) from corrosion. Suchadditional steps may be particularly useful when the structuralconfiguration includes complex geometries such as blind and long narrowchannels. Such additional steps may include dipping the structure,device, component, part, etc. into an inhibitor/water solution for ashort time (e.g. a number of minutes) prior to dipping the structureinto the Au etchant (which may not but preferably does include a nickelcorrosion inhibitor). Normal Au etching can then be allowed to proceed.If necessary, the etching operation may be halted part way through theprocess and re-immersion into the inhibitor solution may be made tooccur so as to provide additional protection for any newly exposedstructural material surfaces. Such operations may be repeated more thanonce if found to be necessary. Appropriate inhibitor immersion times,temperatures, frequency of re-immersion, and other process variables andoptions may be ascertained empirically by those of skill in the art.

Although a diluted etchant increases the total etch time and allows forenhanced control, excessively diluted solutions can not completely etchaway all Au. Those of skill in the art may ascertain empirically usefulranges of effective dilution. It will be understood by those of skill inthe art that though the above discussion focused on Au seed layermaterial and Ni structural material, the process of using a dilutedetchant; an etchant containing a corrosion inhibitor, or inhibitors,specific to the structural material, or materials, to be protected;and/or an inhibitor bath, may be useful with other materials (e.g.sacrificial materials, seed layer materials, or adhesion layermaterials) to be removed and/or with other structural materials. Stillother process parameter modifications from recommended values and/orranges may yield slower/more controlled and better etching results.

For example, the vendor of the titanium etchant recommends using theetchant at 70-80° C. The vendor indicates that the etch rate will beabout 10 Angstroms/second (A/s) at about 10° C. and will be about 50 A/sat 85° C. Again in some embodiments, it is desirable to extend the totaletch time to around 10 min. Since with this material, the etch rate istemperature related, we can lower the operation temp to increase etchtime. An additional advantage in doing this includes decreasedevaporation of the toxic chemicals in the etchant (e.g. HCl). Certainly,if necessary the concentration of the etchant may also be reduced. Testsindicated that sufficient decrease in etch time could be achieved bymodifying the temperature. For example, Ti was etched in 1 minute at 50°C., 3.5 minutes at 40° C., and in about 10-14 minutes at 35° C., and nochange in the Ti layer was observed after 20 minutes when the processwas performed at room temperature.

As HCl in the titanium etchant could cause pitting of Ni or otherstructural materials, in some embodiments, dilution of the etchant,incorporation of an inhibitor therein, or upfront inhibitor treatmentsmay be used in addition to controlling of the temperature at a desiredlevel. The addition of a corrosion inhibitor to the solution may againinvolve use of NaNO3 or a different inhibitor and may involve the addedamounts in the range discussed above or outside of that range. It iswithin the level of skill of those in the art to empirically determineeffective ranges of temperature, inhibitor type and concentration, andthe like without undue experimental effort. Though the discussion oftemperature as a process control variable has been limited to titaniumetchants, it will be clear to those of skill in the art that temperaturecontrol may be used with other materials to be removed, etchants, andstructural materials.

As a result of additional problems discovered with regard to the goldetchant attacking nickel, several additional techniques for enhancingthe removal process are proposed. Each additional enhancement may beused as needed. They may be used alone or in combination with each otheror in combination with the other techniques discussed herein. Inparticular, when using the GE8148 gold etchant, a white precipitate hasbeen observed and when the precipitate has been removed, damage (i.e.corrosion) of the underlying surface of the structural material (i.e.nickel) has been observed. Though not necessarily relevant to theeffectiveness of the solutions to the problem, it is believed that theprecipitate may have a primary source and a secondary source. Theprimary source appears to be a reaction between remnants of a coppersacrificial material that interact with the etching solution to form aprecipitate Cul (Copper-Iodine). The secondary source appears to be aprecipitate that results from a reaction between the gold and theetchant to form AuI (Gold-Iodine). The corrosion may come about from alocalized difference in concentration and/or as a result the localizedpH dropping too low.

To address these issues, some embodiments may benefit fromimplementation of the following enhancements: (1) if the device containscopper, any copper that would be accessible to the gold etchant ispreferably removed prior to bringing the etchant into contact with thecopper; (2) during etching, moderate levels of agitation may be used tokeep stagnant areas from forming what may otherwise become oversaturatedregions; (3) In situations where long channels or blind cavities exist,periodic removal of the structure from the gold etchant may occur andthen the structure may be subjected (e.g. by dipping or the like) to anHCL or C-38 solution which will dissolve the precipitate and prevent anylocal oversaturation from occurring—this process may be repeated severaltimes if necessary during the etching of a given region; and/or (4)instead of using wet etching of the gold, it may be desirable to use dryetching methods (e.g. RIE or Ar bombardment). A book entitled “Etchingin Microsystem Technology”, by Michael Kohler, and published by WileyVCH lists some recipes for etching Titanium-gold layers.

When practicing embodiments where sacrificial seed layer and/or adhesionlayer depositions are based on electroless or direct metallizationtechniques, during the removal processes, it may not only be necessaryto use etchants or removal processes that attack the sacrificialmaterial, the associated seed layer material, and the associatedadhesion layer material, it may also be necessary to use an etchant oretching operation that can remove any materials deposited duringactivation operations, such as palladium, graphite, or the like.

Furthermore, when practicing embodiments where seed layer and/oradhesion layer depositions are based on electroless or directmetallization techniques, it may be that different base materials (i.e.exposed materials that are subjected to activation), will become more orless susceptible to receiving depositions than other materials and assuch beneficial or detrimental properties may result from tendencies toform or not to form coatings with thicknesses that depend on theproperties of the base materials.

FIG. 21 provides a block diagram of primary operations associated with aprocess for forming a multi-layer structure according to anotherembodiment of the invention. Block 601 sets forth a 1^(st) operation ofthe embodiment which involves the preparation of the surface of thesubstrate, or of a previously formed layer, so that it may receive anelectrodeposition of a sacrificial or structural material. Block 611sets forth a 2^(nd) operation of the embodiment which involves theselective deposition of a structural material. Block 621 sets forth a3^(rd) operation of the embodiment which calls for the selectivedeposition of a sacrificial material. Block 631 sets forth a 4^(th)operation of the embodiment which involves depositing a spreadabledielectric material while block 641 sets forth a 5^(th) operation whichinvolves curing the spreadable dielectric material. Block 651 sets fortha 6^(th) operation of the embodiment which involves planarization of thedeposits to a level corresponding to the intended boundary level of thelayer. Block 661 calls for the repetition of Operations 1-6 one or moretimes to build up the multi-layer structure. Block 671 sets forth an8^(th) operation of the embodiment which calls for the release of thestructure from the sacrificial material and from any seed layer materiallocated between layers of sacrificial material.

FIGS. 22A-22H provide schematic illustrations of side views at variousstages of the process of FIG. 2I which provides an embodiment forincorporating a dielectric material along with platable conductivematerials in association with arbitrary layers of a structure beingformed.

In a preferred implementation of the process, a conductive structuralmaterial comprises nickel 702; a dielectric material comprises a UVcurable photopolymer 704; a conductive sacrificial material comprisescopper 706; the surface treatment comprises electroless deposition ofcopper 708. However, in other implementations other materials andmaterial combinations may be used.

In the first operation a surface of the substrate or the surface of apreviously formed layer is prepared so that it may receive anelectrodeposition of a conductive structural material and a conductivesacrificial material. Surface preparation of the substrate may bedifferent than that required for subsequent layers or may be omitted ifthe substrate or immediately preceding layer is (1) entirely conductive,(2) is conductive in appropriate locations (i.e. locations whereelectrodeposition is to occur and such that the locations areconductively connected to a source of electric power), or (3) in theevent that the substrate is supplied with a plating base or seed layeralready in place.

As illustrated in FIG. 22A, the surface treatment 708 is applied overthe entire previous layer or substrate 701. In other embodiments, forexample, the surface treatment may be applied in a patterned manner soas to either (1) correspond to the dielectric areas on the precedinglayer or (2) correspond to those portions of the dielectric areas on thepreceding layer where electrodeposition is to occur and where necessaryto yield a conductive bridge to a source of electric power.

In this embodiment, the surface preparation preferably involves theelectroless deposition of copper which may be implemented using thefollowing three steps:

-   -   (1) Activate the substrate using a solution of hydrochloric        acid, tin chloride, and palladium chloride where the        concentrations and ratios of each, as well as the general        process parameters that may be used, are known, readily        ascertainable, or are readily obtainable from standard sources        by those of skill in the art.    -   (2) Optionally, rinse the substrate with de-ionized water; and    -   (3) Expose the substrate to an electroless deposition solution        containing sodium hydroxide, formaldehyde, a chelator, and a        copper salt where the relevant concentrations and ratios and        other process parameters are known, readily ascertainable, or        purchasable from standard sources by those skilled in the art.

In other embodiments, other surface preparation processes and materialsmay be used. For example, in some alternative embodiments, one or moreof the following may be used in forming a plating base or seed layeronto which electrodeposition may take place:

-   -   a) A different metal or alloy may be deposited by electroless        deposition. For example, nickel, tin, silver, or another        material may be used;    -   b) A metal or other conductive material or materials may be        applied by a form of PVD (e.g. sputtering or evaporation);    -   c) A metal or conductive compound may be applied by a form of        CVD;    -   d) A metal or conductive compound may be applied by a direct        metallization (i.e. a direct plating technique), for example a        Sn-Pd process may be used, a graphite based process or a        conductive polymer based process may be used.    -   e) Any of the alternatives a)-d) may be followed by a        microetching operation, e.g. using an etchant such as Endplate        AD-485 from Cookson Electronics in order to provide a rougher        surface to improve adhesion to a masking material (e.g.        photoresist) that may be applied in a subsequent step;    -   f) Electroplating of metal may occur directly onto a substrate        or previously formed layer that has undergone the activation        operation described above, or one similar to it, without the        need of a subsequent electroless deposition operation;    -   g) A conductive powder or film may be deposited by mechanical        means (e.g. spraying, spreading, rolling, or the like) and then        if necessary transformed into a solid by, for example, use of        heat, pressure, radiation, application or evaporation of a        solvent, or the like    -   h) A conductive powder may be electrostatically applied;    -   i) A conductive powder may be applied by electrophoretic        deposition;    -   j) Conductive particles may be deposited and adhered via a spray        metal coating process;    -   k) In other alternative embodiments, operations g)-j) may be        accompanied by, for example, use of heat, pressure, radiation,        application and evaporation of a solvent, or the like to enhance        the cohesion of individual particles, the adhesion of particles        to the substrate or to form a more continuous or dense coating.    -   l) In other alternative embodiments, operations of g)-j) may be        followed by an operation such as that set forth in k) which may        in turn be followed or proceeded by, a compaction operation by        using enhanced pressure, pressing, rolling, vibration, or        peening.

m) In other alternative embodiments, the surface preparation step may beskipped. This is especially appropriate for situations where it isdesired that the next layer of the structure is to be made from adielectric material only or where the entire structure is to be madefrom the dielectric material (i.e., without a structural metal).

FIG. 22B depicts the state of the process after completion of Operation(2) of FIG. 21, i.e. after selective deposition of a structuralmaterial. In FIG. 22B, structural material 702 is shown as having beenselectively deposited using a contact mask (e.g. of the anodeless type)or an adhered mask (e.g. of patterned photoresist). Since some desirablestructural materials may plate with less than 100% plating efficiency,it may be necessary or desirable to take some precautionary orcorrective actions to reduce bubble formation or to remove bubbles onceformed. For example, the plating bath may be degassed prior to mating toenhance its ability to hold gas in solution should bubbles begin toform.

FIG. 22C depicts the state of the process after Operation (3) of FIG.21, i.e. after selective deposition of sacrificial material. In FIG.22C, sacrificial material 706 is selectively deposited using a contactmask (e.g. of the anodeless type) or an adhered mask (e.g. of patternedphotoresist). The contact material of the mask should mate to thesurface of the substrate or previously formed layer to shield thoseportions of the layer where a dielectric material will eventually belocated. As plating efficiency may also be an issue during this step,some precautionary or corrective operations may be appropriate duringperformance of this operation. Such operations were discussed above inassociation with FIG. 22B.

In some contact mask implementations, it may be necessary for theconductive sacrificial material locations to be offset from theconductive structural material locations by a minimum width of themasking material. This may be termed that “minimum critical offset” or“MCO” (which, for example, may be in the range of 2-5 μm in some inembodiments while it may be more or less in other embodiments). Such anoffset may be necessary in order to prevent mechanical conflict betweenthe contact material of the mask and the previously deposited structuralmaterial.

As a result of the process order of this embodiment (i.e. deposit ofconductive structural material followed by deposit of conductivesacrificial material followed by deposit of dielectric material) thedielectric material and structural material will not generally be indirect contact with one another on any single layer. In certaincircumstances, however, such direct contact may be possible such as whencertain mask types are used and when a region of structural material isto be completely surrounded by a ring of dielectric material. In anyevent, connections between conductive structural material and dielectricmaterial may be made via higher and lower bounding layers.

In some alternative embodiments, the order of processing may be changed(e.g., deposition of conductive structural material may be followed bydeposition of dielectric material which may be followed by deposition ofconductive sacrificial material). In such embodiments, conductivestructural material and dielectric material could be in contact, butthis would generally result in the first of a dielectric or structuralmaterial being surrounded by the second of them. This might be apreferred approach for the formation of certain structures.

In other embodiments, the use of adhered masking techniques may removethe restrictions associated with the minimum critical offset notedabove. In some such embodiments, contact masking may be used duringdeposition of the structural material and adhered masking may be usedduring the deposition of the sacrificial material. In other embodiments,adhered masking may be used during the deposition of both the conductivestructural material and the conductive sacrificial material. Analogousvariations exist when the order of processing is changed.

In still other alternative embodiments, the sacrificial material may beblanket deposited so as to remove issues associated with the MCO, thenthe deposited materials may planarized to a desired height (e.g. a levelthat is somewhat above the level associated with the intended layerthickness), a contact or adhered mask may be applied to a planed surfaceand then either the structural material and/or the sacrificial materialmay be etched to an appropriate depth so as to define voids forreceiving a dielectric material in a next step. These same alternativesmay be applied when the processing order of the structural andsacrificial materials is reversed.

In Operation (4) of FIG. 21 a dielectric material is to be deposited. Inthe present embodiment it is preferred that the dielectric material 704be a UV curable resin or other spreadable material. There are a varietyof dielectric materials that may be deposited in this step using anumber of different deposition methods. A preferred method is to use acurable stereolithography resin or paste. For example, SL5190 epoxyphotopolymer resin manufactured by Vantico, AccuDur 100 sold by 3DSystems, or Somos 9120 sold by Dupont would be suitable. Thermally curedmaterials may are also suitable and may be used in alternativeembodiments.

In the present embodiment, a two operation process is used in depositingthe dielectric material 704:

-   -   (1) The substrate surface (in whole or in part) is coated with        the dielectric material 704. FIG. 22D depicts the state of the        process after the substrate has been coated and partially        leveled.        -   a) Preferably this is done with the substrate horizontal,            face-up, and the dielectric material applied by pouring onto            the substrate surface.        -   b) Alternatively, the substrate may be dipped (with a            substantially vertical orientation) into the dielectric            material and then slowly withdrawn.        -   c) Alternatively, the dielectric material may be applied by            a spreader bar which pumps the dielectric material through            nozzles pointed in the direction of the substrate which is            preferably oriented horizontally and face up.        -   d) Alternatively, the dielectric material may be applied by            orienting the substrate horizontally and dipping into the            dielectric material and then slowly withdrawing the            substrate.        -   e) Alternatively, the dielectric material may be applied in            conjunction with one of the ‘leveling’ operation            alternatives described hereafter.    -   (2) The dielectric material is ‘leveled’ to establish the        appropriate thickness and an approximately uniform distribution        of material across the substrate.        -   a) Preferably this leveling is performed using a doctor            blade 720 as shown in FIG. 22D (after partial leveling). The            doctor blade is (i) aligned to sweep a plane that is            parallel to the plane of the substrate, (ii) located a fixed            distance away from the surface of the preceding layer (e.g.            at the layer thickness or somewhat higher), and (3) moved in            a controlled manner across the substrate from one side to            the other. Blade geometry, spacing from the previously            formed layer, speed of travel, and number of sweeps can be            optimized for various materials empirically as necessary.        -   b) Alternatively, in other embodiments, this step may be            performed by spinning the dielectric coated substrate at a            rate appropriate to establish the desired thickness.            Appropriate speed and duration of the spinning may depend on            the properties of the dielectric material and may readily be            determined experimentally by those of skill in the art in            view of the teachings herein.        -   c) In other embodiments, a roller may be used in place of            the doctor blade. The roller may rotate with the direction            of motion or counter to it        -   d) In still other embodiments, the dielectric material may            be dispensed from a cavity in the doctor blade as the doctor            blade is moving across the preceding layer.        -   e) In still other embodiments, the substrate may be oriented            horizontally, vertically, or at an angle to the horizontal            and gravity may be allowed to provide the leveling force.        -   f) In still other embodiments, the leveling operation of            this step may be skipped in favor of a planarization step            that will follow.

In various alternative embodiments, different types of dielectrics maybe used, for example, the dielectric material may comprise:

-   -   (1) A one-part epoxy system.    -   (2) A two-part epoxy system.    -   (3) A three-part epoxy system.    -   (4) A one-part PDMS system.    -   (5) A two-part PDMS system.    -   (6) Sylgard 184 (PDMS) from Dow Corning, mixed in appropriate        ratio before application.    -   (7) Photoneece® PWDC-1000 (polyimide) from Dow Corning.    -   (8) An oxide or nitride deposited through low pressure chemical        vapor deposition (LPCVD).    -   (9) A low stress SiN (silicon nitride) deposited through LPCVD.    -   (10) A fusible powder or non-fusible powder where individual        particles may be coated with a fusible material. In some such        alternatives, the particles may be compacted against the surface        of the previous layer with a roller during or subsequent to        deposition. In some such alternatives, the ‘cure’ may be        performed by heating the dielectric material (e.g. by laser        heating). In some such embodiments, particles in the range of 5        μm to 10 μm are preferred, but particles in the range of 10 μm        to 100 μm can also be used in some embodiments.    -   (11) Any of the materials of 1-10 may be used in combination        with an incorporated ferrite powder suspended in the spreadable        material to increase its usefulness in transformers, inductors,        and the like.    -   (12) Any of the materials 1-10 may be used in combination with        an incorporated metal or ceramic powder suspended in the        spreadable material to increase strength or toughness or to        provide a surface more amenable to planarization.

In Operation (5) the spreadable dielectric material is cured. In FIG.22E the dielectric material has been preferentially cured by exposure toUV radiation (preferably in the range of 320 nm to 400 nm), for example,through the use of a florescent UV light source such as F71 from UValux.In alternative embodiments other sources of curing radiation may be usedand even other types of curable materials, for example:

-   -   (1) A UV mercury lamp may be used.    -   (2) A UV flood source may be used.    -   (3) A UV laser source may be used wherein the wavelength(s),        scan pattern, speed, etc., may be optimized to reduce distortion        and increase adhesion.    -   (4) The dielectric material may be cured in response to        radiation in the visible spectrum with light sources and        background radiation being appropriately modified.    -   (5) The dielectric material may be cured in response to        radiation in the infrared spectrum with radiation sources and        background radiation being appropriately modified.    -   (6) The dielectric material may be cured through the use of        heat, radiated, conducted, or convected to the dielectric        material or via any combination of these possibilities.    -   (7) The dielectric material may be cured through contact with        the air.    -   (8) The dielectric material may be cured through an endothermic        or exothermic reaction within the dielectric material.    -   (9) In some embodiments, the dielectric material may not be        cured, but may be useable as deposited. This may be the case,        for example, for certain gels and compacted powders.

In Operation (6) of FIG. 21, planarization of the deposited materialsoccurs. In FIG. 22F the desired layer thickness, LT, and surface finishis established preferably by fly cutting (e.g. using a diamond tippedtool) with endpoint detection being made by periodically pausing thediamond fly cutting and measuring the layer thickness using an LVDT orother contact measurement technique. In other embodiments, otherplanarization or trimming techniques may be used.

-   -   (1) Alternative planarization operations may comprise lapping        with crystalline or poly-crystalline diamond.        -   a. The media size may be between 0.5 to 3.0 μm, between 3.0            to 6.0 μm or even larger (particularly where a multi-stage            trimming process will be used—starting with coarser media            and working toward finer media as the desired planarization            height is achieved.    -   (2) The planarization may comprise lapping using a ceramic        media.    -   (3) The planarization may comprise use of fixed media lapping.    -   (4) The planarization may comprise use of a Renewable Polishing        Lap as described in U.S. Pat. No. 5,897,424 to Evans, et al.        This patent is hereby incorporated herein by reference as if set        forth in full.    -   (5) The planarization may comprise use of two or more lapping        operations with operations being varied in at least one of:        lapping media, lubricant, pressure, duration, speed, or motion        profile.    -   (6) The planarization may comprise one or more lapping        operations followed by one or more diamond fly cutting        operations.    -   (7) The planarization may comprise one or more diamond fly        cutting operations followed by one or more lapping operations.    -   (8) In addition to planarization including fly cutting or one or        more of the operations 1.-7. it may also include one or more        polishing operations.    -   (9) In addition to planarization including fly cutting or one or        more of the operations of 1.-7., it may also include performance        of an endpoint detection measurement, e.g. using a confocal        laser measurement system, a physical probe contact system, an        eddy current measurement system, sonic means, x-ray measurement.

Further teachings about planarizing layers and setting layer thicknessesand the like are set forth in the following U.S. Patent Applications:(1) U.S. Patent Application No. 60/534,159, filed Dec. 31, 2003, byCohen et al. and which is entitled “Electrochemical Fabrication Methodsfor Producing Multilayer Structures Including the use of DiamondMachining in the Planarization of Deposits of Material”; (2) U.S. PatentApplication No. 60/534,183, filed Dec. 31, 2003, by Cohen et al. andwhich is entitled “Method and Apparatus for Maintaining Parallelism ofLayers and/or Achieving Desired Thicknesses of Layers During theElectrochemical Fabrication of Structures”; and (3) U.S. patentapplication Ser. No. 11/029,220, Jan. 3, 2005, by Frodis, et al., whichis entitled “Method and Apparatus for Maintaining Parallelism of Layersand/or Achieving Desired Thicknesses of Layers During theElectrochemical Fabrication of Structures”. These patent filings areeach hereby incorporated herein by reference as if set forth in fullherein.

In Operation (7), operations 1.-6. are repeated as necessary to build upthe structure from a plurality of adhered layers. The state of theprocess after forming four layers is illustrated by layers L1-L4 of FIG.22G.

In Operation (8), the structure is released. Once the build is complete(e.g. formation of all layers are completed), the structure is releasedfrom any sacrificial material as shown in FIG. 22H. In some embodiments,the build may be singulated (i.e. diced) before release. Preferably, thestructure is released by using an etchant that attacks the sacrificialmaterial and exposed regions of any surface treatment material depositedbetween adjacent levels of sacrificial material. The etching operationspreferably do not attack the build material or attack it only at asignificantly lower rate. In the preferred embodiment, the structuralmaterial is nickel, the sacrificial material is copper and the surfacetreatment is electroless copper. In this scenario, the preferred etchantis a modified version of C-38 from Enthone where the modificationincludes the addition of corrosion inhibitor that helps protect thenickel.

In some alternatives, however, the surface treatment may not be amenableto removal by the same etchant that removes the sacrificial material. Inthese situations, it is necessary to use repeated cycles of twoetchants. For example, sacrificial material etching, followed by asurface treatment etching operation, followed by a sacrificial materialetching operation, etc. until the entire structure has been released (itmay be desirable to have rinse operations occur between the sacrificialand surface preparation etch cycles).

Various additional alternatives to the process of FIG. 21 are possible.In a first group of alternative embodiments, additional steps may betaken to eliminate seed layer material or conductive surface treatmentmaterial from between regions of dielectric material on successivelayers. For example, prior to performing Operation (4), an etchingoperation may be performed that selectively attacks the seed layermaterial and removes it where the dielectric material is to bedeposited. In other alternative embodiments, it may not be necessary forthe etchant to selectively attack the seed layer material but instead itmay attack the conductive structural material as well and/or theconductive sacrificial material but due to the fact that the seed layermaterial is much thinner than the structural and sacrificial materials,it may be possible to remove the seed layer material prior to doingsignificant damage to the other materials.

In a second group of alternative embodiments, or as an add-on to thefirst group of alternative embodiments, it may be possible to locate adifferent seed layer material between regions of structural material onsuccessive layers and regions of sacrificial material on successivelayers. In still further alternatives, it may be possible to achieveetch stop barriers or at least effective etch stop barriers in regionswhere structural material overlays structural material on successivelayers. The techniques of these alternative embodiments may be useful inminimizing interlayer adhesion failure as a result of etching operationsthat unintentionally but excessively undercut seed layer or surfacetreatment material located between successive layers of conductivestructural material during the removal of the seed layer material orsurface treatment material located between successive layers ofconductive sacrificial material.

To locate a different seed layer material between regions of conductivestructural material on successive layers and regions of conductivesacrificial material on successively layers, two additional operationsmay be added between Operations (2) and (3) of FIG. 21. The first ofthese operations includes the etching away of seed layer or surfacetreatment material that is not overlaid by conductive structuralmaterial. Thus the seed layer material or surface treatment material ofOperation (1), block 601, may use a seed layer that is desirable for usebetween regions of structural material located on successive layers butnot regions of sacrificial material located on successive layers. Thesecond of these operations includes depositing a seed layer materialinto the regions of the previous layer exposed by the etching operation(the seed layer may also overlay the already deposited structuralmaterial. After this second operation, the process may continue asoutlined in FIG. 21.

The added operations of the first and second groups of alternativeembodiments are set forth in the block diagram of FIG. 23 where elementssimilar to those of FIG. 21 are indicated with like reference numerals.Blocks 613 and 615 specify operations (2.1) and (2.2) respectively.Operation (2.1) calls for etching away of the exposed portions of theseed layer or surface treatment material created in Operation (1).Operation (2.2) calls for the performance of a second surface treatmentoperation that applies an appropriate seed layer or surface treatmentmaterial to regions where sacrificial material is to be deposited (andpossibly to regions where dielectric material is to be deposited). Toimplement the first group of alternative embodiments, an additionaloperation may be added to the above operations as indicated by Operation(3.1) of FIG. 23 (block 623) which calls for the etching of exposedregions of the second seed layer so that the seed layer material may beremoved from regions of dielectric material that overlay one another onsuccessive layers.

In a third group of alternative embodiments, the enhancements of thefirst and second group of alternative embodiments may be added, mutatismutandis, to embodiments where the order of deposition of structural andsacrificial materials is reversed.

In a fourth group of alternative embodiments, the order of processing ofthe dielectric material, the conductive structural material, andconductive sacrificial material may be changed to have the dielectricmaterial be the first or second material deposited with the other twomaterials being deposited as the first and third materials or as thesecond and third materials and in either order.

In a fifth group of alternative embodiments, the process of the firstand second alternative embodiments may be added singly or together asenhancements to the fourth group of embodiments.

In still another group of alternative embodiments (i.e. the sixth suchgroup) avoidance of unintended etching of seed layer material frombetween regions of structural conductive material deposited onsuccessive layers may achieved without use of 2^(nd) seed layermaterials. In some variations, the methods may be combined with the useof a 2^(nd) seed layer material particularly when the structuralmaterial is to be deposited after the sacrificial material. Theenhancements of these alternative embodiments allow structural materialassociated with a given layer to overlay and directly contact structuralmaterial on a previous layer (over all or part of the common region orregions) or to allow structural material to be deposited onto a seedlayer material that occupies only a portion of the region whereconductive structural material is to exist on the present layer (if allof the region or regions where the structural material was to bedeposited were to be occupied by the seed layer material then the buildtechnique would fall within the first to fifth groups of alternativeembodiments. This enhancement may be achieved in different waysdepending on whether the conductive sacrificial material or conductivestructural material is to be deposited first. In either case, a firstseed layer material may be selectively deposited in a desired pattern orit may be blanket deposited and then later etched to form voids thereinhaving the desired pattern. In some embodiments, a patterned mask usedin depositing the seed layer material may be used in the selectivedeposition of the conductive sacrificial material while any mask used inthe etching of the seed layer material may be used in the selectivedeposition of the conductive structural material and/or in the selectivedeposition of any desired 2^(nd) seed layer material prior to depositingthe conductive structural material. In variations of these alternatives,the selected pattern of openings in the seed layer may take a variety offorms that comprise:

-   -   (1) A narrow region defining the boundary of the common region        between structural material on the immediately preceding layer        and structural material on the present layer;    -   (2) A thin region defining an inwardly offset boundary of the        common region between structural material on the immediately        preceding layer and on the present layer;    -   (3) The entire region or regions that are common to the intended        location of structural material on the immediately preceding        layer and structural material on the present layer;    -   (4) The entire region or regions, with the exception of possibly        a boundary region (that may be used to ensure conductive contact        for all regions of the layer) that define the common region        between structural material on the immediately preceding layer        and on the present layer;    -   (5) Any of patterns (1)-(4) with the exception that one or more        relatively narrow seed layer fingers may extend over or through        selected portions of the common regions (this helps ensure the        existence of a legitimate conductive path to ensure that plating        can occur everywhere.    -   (6) Any desired pattern of openings in the seed layer in the        common region that will allow direct bonding between regions of        the conductive material located on separate layers    -   (7) So long as all regions that are to receive sacrificial        conductive material and conductive structural material have        conductive material located below them (either as a result of        conductive material on the previous layer or as a result of the        seed layer deposited on the present layer) and so long as all        such regions are connected by adequately conductive paths, the        openings may also call for the removal of seed layer material        from those portions of the present layer where dielectric        material is to be located.

Once the desired pattern of openings is obtained, the structuralmaterial may be selectively or blanket deposited or if desired a secondseed layer material may be deposited first.

In a seventh group of alternative embodiments, enhancements of the sixthgroup of embodiments may be applied, mutatis mutandis, to the removal ofseed layer material that is located between regions of conductivesacrificial material on successive layers. Such removal may aid ineffective release of the structure after it is formed.

In an eighth group of alternative embodiments, the conductive structuralmaterial, the conductive sacrificial material, or the dielectricmaterial that is to be deposited first, may be deposited in a blanketmanner as opposed to in a selective manner and then it may beselectively etched to form patterned regions where one or both of theother materials will be deposited.

In a ninth group of alternative embodiments, more than one conductivestructural material, more than one conductive sacrificial material,and/or more than one dielectric material may be used. Depending on theselective patterning method chosen, the ‘minimum critical offset’ mayplay a role in the types of structures that can be successfully formed.

In a tenth group of alternative embodiments, only two materials will bedeposited on some layers (e.g. a conductive structural material and aconductive sacrificial material or a conductive sacrificial material anda dielectric material). Such embodiments may only require one selectivemasking operation per layer. Such embodiments may provide a costeffective approach for fabricating certain structures and would allowmetal structures to be electrically isolated from the substrate.

In an eleventh group of alternative embodiments, an unpatterneddielectric deposition may be used to isolate metal structures from aconductive substrate.

In a twelfth group of alternative embodiments, structures that areextruded geometries in the Z-direction (i.e. the stacking direction ofthe layers, i.e. the direction perpendicular to the plane of layers) orwhich have a reduced cross-section in Z (i.e., no unsupported regions),the steps related to depositing a sacrificial material may be skipped.

In a thirteenth group of alternative embodiments, additional post layerformation operations may be performed. For example diffusion bonding maybe performed to enhance interlayer adhesion.

Particular applications of some embodiments of the invention areillustrated in FIGS. 24A-24J, FIGS. 25A-25H, and FIGS. 26A-26J. In theillustration of FIGS. 24A-24J, the lower portion of a structure isformed from layers of a 1^(st) conductive material and a dielectricmaterial while the upper portions of the structure are formed fromlayers of 1^(st) and 2^(nd) conductive materials where the 1^(st)conductive material in the lower portion of the structure will be astructural material and the 1^(st) conductive material in the upperportions will be removed as a sacrificial material. The 2^(nd)conductive material, in combination with the dielectric material willact as a cap to protect that portion of the 1^(st) conductive materialthat is to remain as part of the structure. Such processing may be used,for example, to form RF devices. Operations for forming the lowerportion of the structure include:

-   -   (1) Selectively depositing a metal (e.g. a metal desired for its        electrical properties, such as copper, gold, or silver) using a        patterned photoresist and, for example, electroplating.    -   (2) Removing photoresist and thereafter filling spaces in the        patterned metal with a dielectric material. The dielectric        material may be a photoresist (if the same as the patterning        resist—it did not need to be removed), polimide, glass, or any        other dielectric material. One example is using Futurrex        Protective Barrier Coating 3-6000. This material has a        dielectric constant of 2.5 and can be cured at 150° C.    -   (3) After the dielectric is hardened, planarizing both metal and        the dielectric material. A variety of techniques can be used,        including but not limited to fly-cutting, lapping, CMP, and        mechanical polishing.

(4) After the layer is planarized, depositing a seed layer. The seedlayer can be, for example, evaporated or sputtered, and can be copper orany other platable metal.

-   -   (5) Patterning the planarized layer with photoresist or a        photosensitive polymer and then plating the desired metal.    -   (6) Removing (e.g. stripping) the photoresist and thereafter        removing the seed layer using a wet etch or anisotropic etch.    -   (7) Repeating the operations of 1.-6. as necessary to form all        layers to form a structure or partially completed structure that        includes a desired metal and a dielectric. As it is intended        that both the dielectric and metal form part of the structure,        no sacrificial etch is used to remove either.

This process has several advantages: (1) It can prevent the metal fromoxidizing; (2) The dielectric helps support the metal and may make thestructure more rigid, provide self packaging, and protection from shockand vibration, and (3) Use of the dielectric material may allowproduction of smaller electric devices, for example capacitors, RFdevices, and the like.

After the parts (e.g. the lower layers of a structure) are encased,movable parts (e.g. the upper layers of a structure) can be fabricatedon top. For example, some electric components can be encased within thelower layers and movable devices and/or other electric component can befabricated in the upper layers. A cap of a 2^(nd) conductive material(e.g. nickel) may be used to protect the encased 1^(st) conductivematerial (e.g. copper) from an etchant that will be used to remove itfrom the upper layers. Of course in alternative embodiments, reversal ofthe order of forming metal/metal and dielectric/metal layers mayreversed or even alternatingly used.

FIGS. 24A-24J depicts schematic side views various states of thisdielectric/metal (e.g. dielectric/copper) and metal/metal (e.g.nickel/copper) fabrication process as applied to a specific structure.FIG. 24A depicts patterned copper 802 with photoresist 804 on asubstrate 800. FIG. 24B depicts a coating of dielectric 806 fillingvoids in the copper where the photoresist was located. FIG. 24C depictsplanarized dielectric 806 and copper 802. FIG. 24D depicts a depositedcopper seed layer. FIG. 24E depicts a second layer of patterned copperwith photoresist. FIG. 24F depicts that the photoresist has been removedand that exposed portions of the seed layer have been removed. FIG. 24Gdepicts the lower layers of a structure formed from copper and adielectric (e.g. a passive RF component) after repeated operations havebeen performed to complete formation of the second layer and subsequentlayers. FIG. 24H depicts formation of a capping pattern 812-B of a2^(nd) metal, e.g. nickel, deposited (e.g. in a patterned photoresist)on a seed layer 812-A of the 2^(nd) metal. FIG. 24I depicts the state ofthe process after removal of the exposed portions of the seed layer,deposit of the 1^(st) conductive material, planarization and formationof subsequent layers of 1^(st) and 2^(nd) conductive materials (e.g.copper and nickel). FIG. 24J depicts the state of the process after thesacrificial portions of the 1^(st) conductive material have been removed(e.g. by chemical etching).

FIGS. 25A-25H and FIGS. 26A-26J illustrate two methods for having threematerials on the same layer. These processes avoid doing lithography ona layer with topography. These processes can be used for manyapplications. This process can be used, for example, to make tips forspring probes using a different material for each or to maketransformers or electronic components that require permalloy, asacrificial metal and another structural metal on the same layer, or ina process where a dielectric material and two metals are required oneach layer. In alternative processes the procedures may be extended toallow four or more materials to be placed on each layer. These methodsmay be used with positive resists and possibly with negative resists.The basic process operation, includes: (1) Depositing photoresist,depicted in FIG. 25A and FIG. 26A, (2) exposing a first pattern for afirst material to be deposited, depicted in FIG. 25B and FIG. 26B, (3)developing the first pattern to make openings in the photoresist fordepositing the first material, depicted in FIG. 25C and FIG. 26C, (4)exposing the second pattern on the same resist layer defining locationswhere a first material is to be deposited, depicted in FIG. 25D and FIG.26D , (5) depositing the first material, for example nickel, depicted inFIG. 25E and FIG. 26E, (6) developing the second pattern, depicted inFIG. 25F and FIG. 26F, (7) depositing the second material within thesecond pattern, depicted in FIG. 25G and FIG. 26G, and either (8A)planarizing the photoresist, first material, and second material tocomplete formation of the layer, depicted in FIG. 25H, or (8B) removingthe photoresist, depicted in FIG. 26H, then depositing a third material,depicted in FIG. 26I, and then planarizing, depicted in FIG. 26J.

In further alternative embodiments the processes of FIGS. 25A-25H and26A-26J may be extended to the formation of additional layers. Asnecessary seed layer and removal operations may be added when dielectricsubstrates are used or when dielectric materials will be depositedduring layer formation. Various other alternatives and modificationswill be apparent to those of skill in the art upon review of theteachings herein.

Additional teachings, which may supplement the teaching set forthexplicitly herein, concerning the formation of structures on dielectricsubstrates and/or the formation of structures that incorporatedielectric materials into the formation process and possibility into thefinal structures as formed are set forth in a number of additionalpatent applications. The first of these applications is U.S. PatentApplication No. 60/534,184, filed Dec. 31, 2004, by Cohen, et al., whichis entitled “Electrochemical Fabrication Methods IncorporatingDielectric Materials and/or Using Dielectric Substrates”. The second ofthese applications is U.S. Patent Application No. 60/533,932, filed Dec.31, 2004, by Cohen, et al., which is entitled “ElectrochemicalFabrication Methods Using Dielectric Substrates”. The third of theseapplications is U.S. Patent Application No. 60/533,891, filed Dec. 31,2004, by Lockard, et al., which is entitled “Methods forElectrochemically Fabricating Structures Incorporating Dielectric Sheetsand/or Seed layers That Are Partially Removed Via Planarization”. Afourth such filing is U.S. Patent Application No. 60/533,895, filed Dec.31, 2004, by Lembrikov, et al., which is entitled “ElectrochemicalFabrication Method for Producing Multi-layer Three-DimensionalStructures on a Porous Dielectric” Each of these patent applications ishereby incorporated herein by reference as if set forth in full herein.

Further teachings about planarizing layers and setting layersthicknesses and the like are set forth in the following U.S. PatentApplications: (1) U.S. Patent Application No. 60/534,159, filed Dec. 31,2004, by Cohen et al. and which is entitled “Electrochemical FabricationMethods for Producing Multilayer Structures Including the use of DiamondMachining in the Planarization of Deposits of Material”; (2) U.S. PatentApplication No. 60/534,183, filed Dec. 31, 2004, by Cohen et al. andwhich is entitled “Method and Apparatus for Maintaining Parallelism ofLayers and/or Achieving Desired Thicknesses of Layers During theElectrochemical Fabrication of Structures”; and (3) U.S. patentapplication Ser. No. 11/029,220, Jan. 3, 2005, now U.S. Pat. No.7,271,888, by Frodis, et al., and entitled “Method and Apparatus forMaintaining Parallelism of Layers and/or Achieving Desired Thicknessesof Layers During the Electrochemical Fabrication of Structures”. Each ofthese patent applications are hereby incorporated herein by reference asif set forth in full herein.

As noted herein above some embodiments may employ diffusion bonding orthe like to enhance adhesion between successive layers of material.Various teachings concerning the use of diffusion bonding inelectrochemical fabrication processes are set forth in U.S. patentapplication Ser. No. 10/841,384, filed May 7, 2004, now abandoned, byZhang, et al., and which is entitled “Method of ElectrochemicallyFabricating Multilayer Structures Having Improved Interlayer Adhesion”.The techniques disclosed in this referenced application may be combinedwith the techniques and alternatives set forth explicitly herein toderive additional alternative embodiments. This application is herebyincorporated herein by reference as if set forth in full.

As noted herein before, some embodiments may employ mask based selectiveetching operations in conjunction with blanket deposition operations.Some embodiments may form structures on a layer-by-layer basis butdeviate from a strict planar layer on planar layer build up process infavor of a process that interlaces material between the layers. Suchalternative build processes are disclosed in U.S. application Ser. No.10/434,519, filed on May 7, 2003, now U.S. Pat. No. 7,252,861, entitled“Methods of and Apparatus for Electrochemically Fabricating StructuresVia Interlaced Layers or Via Selective Etching and Filling of Voids”.The techniques disclosed in this referenced application may be combinedwith the techniques and alternatives set forth explicitly herein toderive additional alternative embodiments. This patent application isherein incorporated by reference as if set forth in full.

Further alternative embodiments are possible by combining the methodsdisclosed explicitly herein with the techniques disclosed in U.S. patentapplication Ser. No. 10/841,272, filed on May 7, 2004, now abandoned, byAdam Cohen et al., and entitled “Methods and Apparatus for FormingMulti-Layer Structures Using Adhered Masks”. This referenced applicationis incorporated herein by reference as if set forth in full herein. Thisreferenced application teaches various electrochemical fabricationmethods and apparatus for producing multi-layer structures from aplurality of layers of deposited materials where some of the depositedmaterials are selectively deposited via an adhered mask that istemporarily contacted to the substrate or a previous formed layer ordeposit of material.

Further alternative embodiments are possible by combining the methodsdisclosed explicitly herein with the techniques disclosed in any or allof the following patent applications: (1) U.S. patent application Ser.No. 10/697,597 filed on Oct. 29, 2003, now abandoned, by Michael S.Lockard et al. and entitled “EFAB Methods and Apparatus Including SprayMetal or Powder Coating Processes”; (2) U.S. patent application Ser. No.10/841,383 filed May 7, 2004, now U.S. Pat. No. 7,195,989, by Lockard,et al., and entitled “Electrochemical Fabrication Methods Using TransferPlating of Masks” and/or with the techniques disclosed in U.S. patentapplication Ser. No. 10/607,931 filed on Jun. 27, 2003, now U.S. Pat.No. 7,239,219, by Elliot R. Brown et al. and entitled “Miniature RF andMicrowave Components and Methods for Fabricating Such Components”; and(3) U.S. patent application Ser. No. 10/841,300, filed May 7, 2004, nowlapsed, by Lockard, et al., and entitled “Methods for ElectrochemicallyFabricating Structures Using Adhered Masks, Incorporating DielectricSheets, and/or Seed layers That Are Partially Removed ViaPlanarization”. These patent applications are hereby incorporated hereinby reference as if set forth in full.

Various other embodiments of the present invention exist. Some of theseembodiments may be based on a combination of the teachings set forthexplicitly herein with various teachings incorporated herein byreference.

In view of the teachings herein, many further embodiments, alternativesin design and uses of the instant invention will be apparent to those ofskill in the art. As such, it is not intended that the invention belimited to the particular illustrative embodiments, alternatives, anduses described above but instead that it be solely limited by the claimspresented hereafter.

We claim:
 1. A batch process for forming a plurality of multilayerthree-dimensional structures, comprising: (a) forming and adhering afirst layer of material directly or indirectly to a dielectric substrateor to a substrate containing at least one region of dielectric material,wherein the first layer comprises at least one structural material andat least one sacrificial material; (b) forming and adhering at least oneadditional layer to a previously formed layer, which may be the firstlayer or a layer formed subsequent to the forming of the first layer, tobuild up the plurality of three-dimensional structures from a pluralityof adhered layers, wherein each of the at least one additional layerscomprises at least one structural material and at least one sacrificialmaterial; and (c) after formation of the plurality of layers removingthe at least one sacrificial material from multiple layers to reveal theplurality of three-dimensional structures; wherein the formation of thefirst layer of material additionally comprises: (i) depositing anadhesion layer material and/or a seed layer material to form anon-planar coating of which a portion defines a region of the substratethat is to receive an electrodeposition of a selected one of astructural material or of a sacrificial material; (ii) removing, viaplanarization, the adhesion layer material and/or the seed layermaterial from an elevated portion of the non-planar coating afterdeposition of the selected one of the at least one structural materialor the at least one sacrificial material; and (iii) planarizing the atleast one structural material and the at least one sacrificial materialto set a boundary level of the first layer.
 2. A batch process forforming a plurality of multilayer three-dimensional structures,comprising: (a) forming and adhering a first layer of material directlyor indirectly to a substrate, wherein the first layer comprises at leastone first sacrificial material and at least one first structuralmaterial; (b) forming and adhering at least one nth layer to apreviously formed (n−1)th layer, which may be the first layer or a layerformed subsequent to the first layer, to build up the plurality ofthree-dimensional structures from a plurality of adhered layers, whereinthe at least one nth layer comprises at least one nth sacrificialmaterial and at least one nth structural material; and (c) afterformation of the plurality of layers removing at least one sacrificialmaterial from multiple layers to reveal the plurality ofthree-dimensional structures; wherein the formation of the nth layerfurther comprises: (i) depositing an adhesion layer material and/or aseed layer material to form a non-planar coating of which a portiondefines a region of the (n−1)th layer that is to receive a deposition ofa selected one of the at least one nth sacrificial material or at leastone nth structural material; (ii) removing, via planarization, theadhesion layer material and/or the seed layer material from an elevatedportion of the non-planar coating after deposition of the selected oneof the at least one nth sacrificial material or the at least one nthstructural material; and (iii) planarizing the at least one nthstructural material and the at least one nth sacrificial material to seta boundary level of the nth layer.
 3. The process of claim 2 wherein thenth layer is the second layer and the (n−1)th layer is the first layer.4. A batch process for forming a plurality of multilayerthree-dimensional structures directly or indirectly on a dielectricsubstrate, comprising: (a) forming and adhering a first layer ofmaterial directly or indirectly to a dielectric substrate or to asubstrate containing at least one region of dielectric material; and (b)forming and adhering at least one layer to a previously formed layer tobuild up the plurality of three-dimensional structures from a pluralityof adhered layers; wherein the formation of the first layer of materialcomprises: (i) depositing a first seed layer material onto the substrateincluding at least some portions of the substrate that are not toreceive a selected one of a structural material and sacrificialmaterial; (ii) depositing a selected one of structural material andsacrificial material onto the first seed layer material over thoseportions of the substrate that are to receive the selected one ofstructural material and sacrificial material, wherein the portions thatare to receive the selected one are less than all portions of thesubstrate; (iii) removing portions of the first seed layer material thatare not located between the selected one and the substrate or locatedadjacent to the selected one; (iv) after removing portions of the firstseed layer depositing a second seed layer material onto those portionsof the substrate that are to receive a non-selected one of thestructural material and sacrificial material; (v) depositing thenon-selected one of the structural material and sacrificial materialonto the second seed layer material over those portions of the substratethat are to receive the non-selected one of structural material andsacrificial material; and (vi) planarizing the deposited selected one ofthe structural material and sacrificial material and the depositednon-selected one of the structural material and sacrificial material toa height corresponding to a desired thickness of the first layer.
 5. Theprocess of claim 4 additionally comprising the deposition of a firstadhesion layer material onto at least those areas of the substrate thatare to receive the selected one of the structural material andsacrificial material.
 6. The process of claim 5 additionally comprisingremoving any first adhesion layer material, after removing the portionsof the first seed layer material that are not covered by the selectedone of the structural material and sacrificial material such thatremaining portions of the first adhesion layer material are located onlybetween the first seed layer material and the substrate.
 7. The processof claim 4 additionally comprising the deposition of a second adhesionlayer material, after removing the first seed layer material onto atleast those areas of the substrate to receive the non-selected one ofthe structural material and sacrificial material.
 8. The process ofclaim 7 additionally comprising removing any second adhesion layermaterial that is not covered by the non-selected one of the structuralmaterial and sacrificial material such that remaining portions of thesecond adhesion layer material are located only between the second seedlayer material and the substrate.
 9. The process of claim 7 additionallycomprising the deposition of a first adhesion layer material onto atleast those areas of the substrate to receive the selected one of thestructural material and sacrificial material.
 10. The process of claim 9wherein the first adhesion layer material is substantially the same asthe second adhesion layer material.
 11. The process of claim 9 whereinthe first adhesion layer material is different from the second adhesionlayer material.
 12. The process of claim 5 wherein the deposition of thefirst seed layer material locates the material on the first seed layermaterial on the substrate in regions extending beyond the regions to beoccupied by the selected one of the structural material and sacrificialmaterial.
 13. A batch process for forming a plurality of multilayerthree-dimensional structures on a dielectric substrate, comprising: (a)forming and adhering a first layer of material directly or indirectly toa dielectric substrate or to a substrate containing at least one regionof dielectric material; and (b) forming and adhering at least one layerto a previously formed layer to build up a plurality ofthree-dimensional structures from a plurality of adhered layers; whereinthe formation of the first layer of material comprises: (i) depositing afirst seed layer material onto the substrate, wherein the deposition ofthe first seed layer material locates the first seed layer material onthe substrate to only those regions to be occupied by a selected one ofthe structural material and sacrificial material and the deposition ofthe first seed layer material results in the first seed layer materialoverlaying a masking material that is located in regions where theselected one of the structural material and sacrificial material is notto be located: (ii) depositing a selected one of structural material andsacrificial material onto the first seed layer material over thoseportions of the substrate that are to receive the selected one ofstructural material and sacrificial material, wherein the portions thatare to receive the selected one are less than all portions of thesubstrate; (iii) removing the masking material and removing portions ofthe first seed layer material that are not located between the selectedone and the substrate; (iv) depositing a second seed layer material ontothose portions of the substrate that are to receive a non-selected oneof the structural material and sacrificial material; (v) depositing thenon-selected one of the structural material and sacrificial materialonto the second seed layer material over those portions of the substratethat are to receive the non-selected one of structural material andsacrificial material; and (vi) planarizing the deposited selected one ofthe structural material and sacrificial material and the depositednon-selected one of the structural material and sacrificial material toa height corresponding to a desired thickness of the first layer. 14.The process of claim 6 wherein the deposition of the second seed layermaterial results in the second seed layer material overlaying regionsoccupied by the selected one of the structural material and sacrificialmaterial.
 15. The process of claim 6 wherein the deposition of thesecond seed layer material results in the second seed layer materialbeing only located to those regions where the second material is to belocated.
 16. A batch process for forming a plurality of structures andadhering a layer of material to, comprising: (a) depositing a first seedlayer material directly or indirectly onto a dielectric substrate or toa substrate having at least one region of dielectric material; (b)depositing the selected one of structural material and sacrificialmaterial onto the first seed layer material over those portions of thesubstrate that are to receive the selected one of structural materialand sacrificial material, wherein the portions that are to receive theselected one are less than all portions of the substrate; (c) removingportions of the first seed layer material that are not located betweenthe selected one and the substrate or located adjacent to the selectedone; (d) depositing a second seed layer material onto those portions ofthe substrate that are to receive a non-selected one of the structuralmaterial and sacrificial material; (e) depositing the non-selected oneof the structural material and sacrificial material onto the second seedlayer material over those portions of the substrate that are to receivethe non-selected one of structural material and sacrificial material;and (f) planarizing the deposited selected one of the structuralmaterial and sacrificial material and the non-selected one of thestructural material and sacrificial material to a height correspondingto a desired thickness of the first layer.